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Mastiff puppies and dogs in Denver, Colorado

Looking for a Mastiff puppy or dog in Denver, Colorado? Adopt a Pet can help you find an adorable Mastiff near you.

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Adopt a Mastiff near you in Denver, Colorado

These Mastiffs are available in Denver, Colorado.
Special Needs
No photo available for Sabrina

Sabrina

Mastiff American Bulldog

Female, 7 yrs 9 mos
Boulder, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Needs special attention, Needs experienced adopter, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
Meet Sabrina, a gentle 6-year-old Mastiff mix who’s in need of a special forever home. Sabrina is living with mast cell tumors (MCT) due to cancer and is currently on medication to keep her as comfortable as possible. She requires a loving home that is prepared to offer her hospice care and a peaceful environment. Sabrina can be shy with new people and may give a warning growl or snap if approached when she’s not ready. However, once she builds trust, she becomes deeply affectionate and very attached to her people. She gets along well with mellow dogs and will thrive in a calm household where she can feel safe and loved. If you have a compassionate heart and are ready to provide a supportive and caring home for a special dog like Sabrina, you’ll find a loyal and loving companion in her.

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Photo of Tank

Tank

Mastiff Rottweiler

Male, Puppy
Denver, CO
Size
(when grown) Large 61-100 lbs (28-45 kg)
Details
Good with kids, Good with dogs, House-trained, Shots are up-to-date,
Story
DOB: August or September 2025 Intact because waiting until full grown Personality: He is a really goofy, loving dog. The kind that will melt into you. He likes kids and other dogs. He has been to doggy daycare and boarding without issues. Medium/high puppy energy. He’s food motivated and he does well with training exercises. Likes to hike, go for walks, and play at the dog park. Can play too aggressively for some small dogs. On the purina hydrolyzed diet since June 10. Has had chronic diarrhea on chicken, lamb, and salmon protein based foods. New diet stopped diarrhea. Yay! Dog friendly vegetables and fruit for treats. Reason for Rehoming: I travel 50% of the time for a new job. During my travel periods it’s been hard to train and provide the right activity level. My adult dog, a 5 year old lab, isn’t getting the attention he needs because of the pup as well.

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Photo of Huckleberry

Huckleberry

Mastiff

Male, 1 yr 2 mos
Denver, CO
Size
(when grown) Large 61-100 lbs (28-45 kg)
Details
Good with dogs, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
I’m Huckleberry, a 1 year old male Mastiff mix. I am rather cute, if I do say so myself. Like many young dogs, I can be a little mouthy so may be a bit much for super-young kids, but I would do great with older kids and love attention. I enjoyed the tranquil atmosphere at Movie Night with my Foster family-tbh I slept through most of it! ********PLEASE READ BELOW PRIOR TO EMAILING IN**********If you are interested in adopting this dog or any other from our rescue, please go to https://www.hobocare.org/adopt to review our home requirements and fill out an application. Please do not email and ask for more information on how to adopt, all the information is already available online. The information you see here is all that is currently available about this dog. No boxers are adopted without a completed application and home check. Thank you! ##2619848##

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Photo of Monique

Monique

Mastiff

Female, 4 mos
Littleton, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Good with dogs, Spayed or Neutered, Shots are up-to-date,
Story
Meet Monique! Monique is a 4-month-old Mastiff mix with the sweetest soul who's ready for a fresh start. After being found abandoned in a backyard, this gentle girl sadly ended up on the euthanasia list. Thankfully, she now has a chance to leave that behind and begin her new life. Monique can be a little shy when meeting new people, but it doesn't take long for her loving personality to shine. Volunteers have watched her go from quietly hiding in her kennel to happily wagging her tail, nuzzling hands for affection, and walking nicely on leash. She just needs a little patience and reassurance to feel safe. If you've already fallen in love with Monique, the best way to make her part of your family is to apply to foster her! Our fosters always get the first opportunity to adopt their foster dogs before they become available to the public. Could you be the one to help this deserving puppy start her new life? ##2776213##

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Photo of Zen

Zen

Neapolitan Mastiff Mastiff

Male, 7 yrs 9 mos
Boulder, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Not good with dogs, Needs experienced adopter, Spayed or Neutered, Shots are up-to-date,
Story
Zen is a 6-year-old male Neo Mastiff mix who’s as big-hearted as he is big in stature. Rescued from a shelter after his previous owners surrendered him for being “too big,” Zen is now on the hunt for his forever home where he can truly shine. Zen is a sweet, playful giant with a lot of energy for his breed. He’s very intelligent and learns quickly, making him a joy to train. However, Zen prefers to be the only dog in the home; he can get jealous and aggressive with other dogs, wanting all the attention for himself. When he's your one and only, he’s incredibly loving and will shower you with affection. Though he’s not reactive to other dogs on leash, Zen does best in a home without canine companions. He appreciates careful introductions to new people, especially those who approach unexpectedly. Zen’s ideal owner will be someone experienced with his breed and capable of continuing his training and socialization. If you’re ready to welcome a devoted and energetic companion into your life, Zen could be the perfect fit. He’s looking for a loving home where he can be the center of attention and enjoy all the love he has to give!

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Photo of Bella

Bella

Great Dane Mastiff

Female, Young
Thornton, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Good with kids, Good with dogs, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
Bella is an amazing dog, very friendly, sweet, and well trained. She loves walks and playing with toys. She loves the groomer and is very easy going. My husband has been diagnosed with cancer and we cannot take care of her the way she needs. We are looking for a good home with lots of love and a yard for her to enjoy!

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Or, how about these Mastiffs in cities near Denver, Colorado

These Mastiffs are available for adoption close to Denver, Colorado.
Special Needs
No photo available for Sabrina

Sabrina

Mastiff American Bulldog

Female, 7 yrs 9 mos
Boulder, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Needs special attention, Needs experienced adopter, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
Meet Sabrina, a gentle 6-year-old Mastiff mix who’s in need of a special forever home. Sabrina is living with mast cell tumors (MCT) due to cancer and is currently on medication to keep her as comfortable as possible. She requires a loving home that is prepared to offer her hospice care and a peaceful environment. Sabrina can be shy with new people and may give a warning growl or snap if approached when she’s not ready. However, once she builds trust, she becomes deeply affectionate and very attached to her people. She gets along well with mellow dogs and will thrive in a calm household where she can feel safe and loved. If you have a compassionate heart and are ready to provide a supportive and caring home for a special dog like Sabrina, you’ll find a loyal and loving companion in her.

Learn More

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Photo of Tank

Tank

Mastiff Rottweiler

Male, Puppy
Denver, CO
Size
(when grown) Large 61-100 lbs (28-45 kg)
Details
Good with kids, Good with dogs, House-trained, Shots are up-to-date,
Story
DOB: August or September 2025 Intact because waiting until full grown Personality: He is a really goofy, loving dog. The kind that will melt into you. He likes kids and other dogs. He has been to doggy daycare and boarding without issues. Medium/high puppy energy. He’s food motivated and he does well with training exercises. Likes to hike, go for walks, and play at the dog park. Can play too aggressively for some small dogs. On the purina hydrolyzed diet since June 10. Has had chronic diarrhea on chicken, lamb, and salmon protein based foods. New diet stopped diarrhea. Yay! Dog friendly vegetables and fruit for treats. Reason for Rehoming: I travel 50% of the time for a new job. During my travel periods it’s been hard to train and provide the right activity level. My adult dog, a 5 year old lab, isn’t getting the attention he needs because of the pup as well.

Learn More

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Photo of Huckleberry

Huckleberry

Mastiff

Male, 1 yr 2 mos
Denver, CO
Size
(when grown) Large 61-100 lbs (28-45 kg)
Details
Good with dogs, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
I’m Huckleberry, a 1 year old male Mastiff mix. I am rather cute, if I do say so myself. Like many young dogs, I can be a little mouthy so may be a bit much for super-young kids, but I would do great with older kids and love attention. I enjoyed the tranquil atmosphere at Movie Night with my Foster family-tbh I slept through most of it! ********PLEASE READ BELOW PRIOR TO EMAILING IN**********If you are interested in adopting this dog or any other from our rescue, please go to https://www.hobocare.org/adopt to review our home requirements and fill out an application. Please do not email and ask for more information on how to adopt, all the information is already available online. The information you see here is all that is currently available about this dog. No boxers are adopted without a completed application and home check. Thank you! ##2619848##

Learn More

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Photo of Monique

Monique

Mastiff

Female, 4 mos
Littleton, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Good with dogs, Spayed or Neutered, Shots are up-to-date,
Story
Meet Monique! Monique is a 4-month-old Mastiff mix with the sweetest soul who's ready for a fresh start. After being found abandoned in a backyard, this gentle girl sadly ended up on the euthanasia list. Thankfully, she now has a chance to leave that behind and begin her new life. Monique can be a little shy when meeting new people, but it doesn't take long for her loving personality to shine. Volunteers have watched her go from quietly hiding in her kennel to happily wagging her tail, nuzzling hands for affection, and walking nicely on leash. She just needs a little patience and reassurance to feel safe. If you've already fallen in love with Monique, the best way to make her part of your family is to apply to foster her! Our fosters always get the first opportunity to adopt their foster dogs before they become available to the public. Could you be the one to help this deserving puppy start her new life? ##2776213##

Learn More

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Photo of Zeus

Zeus

Mastiff Rottweiler

Male, Young
Golden, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Spayed or Neutered,
Story
Meet Zeus! This big, playful boy might need a little time to warm up, but once he does, his goofy personality really shines. He's looking for a patient home that will give him the chance to settle in and feel comfortable. Once he opens up, he's all about fun, attention, and making you laugh. Volunteers can't help but gush about him - he's a fun, easy dog to walk, happily taking his time to stop and sniff his favorite spots. He responds to his name, sits when asked, and takes treats with gentle manners. During quiet moments he leans in for soft, reassuring petting, and when the toys come out, his playful side shines!Zeus will only be rehomed to a family without children or with kids at least 10 years of age and without cats, and if considered for a multi-animal home, family must be skilled in managing food resources to mitigate guarding behavior between household dogs. Primary Color: Red Brown Secondary Color: White Weight: 113.2 Age: 1yrs 7mths 0wks

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Photo of Freya

Freya

Mastiff

Female, 4 yrs 1 mo
Aurora, CO
Size
(when grown) Large 61-100 lbs (28-45 kg)
Details
Good with kids, Good with dogs, Spayed or Neutered, Shots are up-to-date,
Story
Hi, I'm Freya! I'm a sweet mama and came with my 9 puppies. I'm a very good girl. I'm said to have had a few litters in the past and I'm ready to put motherhood behind me and have a little time for myself. Won't you spend it with me? If you're interested in adopting me, please fill out an application at www.polkcountyhumanesociety.org/adopt. You can also reserve an appointment to meet me. Some pets are in foster homes or may already have visits scheduled, so appointments help ensure I’ll be available. Polk County Humane Society is located in Bolivar, Missouri, and we welcome adopters from any state. We have access to a transport to Aurora, CO. Other out of state adopters either travel to Missouri or arrange & pay for air transport. Virtual meet and greets are available on the appointment request. ##2755149##

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These pups are in Denver, Colorado too!

Below are our newest added Mastiffs available for adoption in Denver, Colorado. To see more adoptable Mastiffs in Denver, Colorado, use the search tool below to enter specific criteria!
Photo of Zen

Zen

Neapolitan Mastiff Mastiff

Male, 7 yrs 9 mos
Boulder, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Not good with dogs, Needs experienced adopter, Spayed or Neutered, Shots are up-to-date,
Story
Zen is a 6-year-old male Neo Mastiff mix who’s as big-hearted as he is big in stature. Rescued from a shelter after his previous owners surrendered him for being “too big,” Zen is now on the hunt for his forever home where he can truly shine. Zen is a sweet, playful giant with a lot of energy for his breed. He’s very intelligent and learns quickly, making him a joy to train. However, Zen prefers to be the only dog in the home; he can get jealous and aggressive with other dogs, wanting all the attention for himself. When he's your one and only, he’s incredibly loving and will shower you with affection. Though he’s not reactive to other dogs on leash, Zen does best in a home without canine companions. He appreciates careful introductions to new people, especially those who approach unexpectedly. Zen’s ideal owner will be someone experienced with his breed and capable of continuing his training and socialization. If you’re ready to welcome a devoted and energetic companion into your life, Zen could be the perfect fit. He’s looking for a loving home where he can be the center of attention and enjoy all the love he has to give!

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Bonded Pair
Photo of Maggie

Maggie

St. Bernard

Female, 8 yrs 1 mo
Denver, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Good with cats, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
Bonded pair Gus & Maggie come to after Maggie tore her CCL and their previous owner was unable to provide the level of care that she needed. Maggie is almost completely recovered from her TPLO surgery and these two are ready for their happy ever after! Gus can be protective of Maggie, so we recommend a home with no other dogs in it, but they get along just fine with their foster kitty brother! A home with few stairs and a fenced yard would be best for these two. Favorite activities include sunbathing, snowbathing, napping, watching squirrels, and getting belly rubs - in other words, the good life! Adoption application: https://cosaintrescue.org/adopt/

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Photo of Nina

Nina

St. Bernard

Female, 3 yrs 1 mo
Denver, CO
Size
(when grown) X-Large 101 lbs (46 kg) or more
Details
Good with kids, Good with dogs, Good with cats, House-trained, Spayed or Neutered, Shots are up-to-date,
Story
Say hello to Nina! She came into rescue through no fault of her own when her family experienced medical issues and could no longer care for her. Nina has lived successfully with both children and other dogs and enjoys being part of a family. She is house-trained, crate-trained, and settles in nicely to home life. One of her favorite things is spending time with her people—whether that means lounging nearby or snuggling up for some affection. Like many dogs, Nina can be a little protective of especially high-value treats. She needs to eat separate so she can feel secure and doesn't feel like she needs to protect her dinner. The good news is that she communicates her boundaries appropriately and responds well when those signals are respected. Her adopters should be mindful of this behavior and continue to set her up for success through positive management and training. Nina is looking for a family who will appreciate her sweet nature, giant-breed charm, and love of companionship. If you're searching for a loyal best friend who enjoys cuddles as much as she enjoys being part of the family, Nina may be the perfect match. Apply to adopt on our website! https://cosaintrescue.org/adopt/

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Search for a Mastiff puppy or dog

Use the search tool below to browse adoptable Mastiff puppies and adults Mastiff in Denver, Colorado.

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Mastiff puppies and dogs in nearby cities

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Related breeds in Denver, Colorado

Bullmastiffs in Denver, Colorado Neapolitan Mastiffs in Denver, Colorado Saint Bernards in Denver, Colorado

Mastiff shelters & rescues in Denver, Colorado

There are animal shelters and rescues that focus specifically on finding great homes for Mastiff puppies in Denver, Colorado. Browse these Mastiff rescues and shelters below.

Here are a few organizations closest to you:

Rescue

6 miles

Ace of Hearts Dog Rescue - CO Transport Stop

711 Walnut St, Boulder, CO 80203

Pet Types: dogs

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Rescue

6.7 miles

Ho-Bo Care Boxer Rescue

Denver, CO 80209

Pet Types: dogs

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Rescue

7.6 miles

L.O.L.A.'S Rescue

6005 S. Taft Way, Littleton, CO 80127

Pet Types: dogs

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Shelter

7.8 miles

Foothills Animal Shelter

580 McIntyre St., Golden, CO 80401

Pet Types: cats, birds, dogs, rabbits, reptiles, small animals

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Shelter

15.9 miles

Polk County Humane Society (in Missouri) - Colorado Transport

3511 N Salida Court, Aurora, CO 80011

Pet Types: cats, dogs

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Rescue

15.9 miles

Big Dogs Huge Paws, Inc

PO Box 460699, Aurora, CO 80046

Pet Types: dogs

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Shelter

31.6 miles

Soul Dog Rescue

1245 Factory Circle, Fort Lupton, CO 80621

Pet Types: cats, dogs

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Looking for a specific shelter or rescue?

If you're not seeing what you're looking for, try our shelter and rescue search. We have more than 17,000 organizations in our database with furry pals waiting for a new home!

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Want to learn more about adopting a Mastiff puppy or dog?

We've got all the info you need on adopting and caring for a Mastiff puppy. Check out the links below for everything you ever wanted to know about Mastiff puppies and adults.

Mastiff basics

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Where do Mastiffs come from? How many types of Mastiffs are there? From the history of the breed to question about average height, weight and size, brush up on these basic facts about the Mastiff.

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