Introducing a new cat or kitten to your cats

Posted by Jennifer

kittensYou’ve adopted a new cat or kitten, and want to know how to best introduce him or her to other cats in your home? Depending on their age and personalities, you may take days or months to fully integrate your new cat or kitten to your family pets. Below are some guidelines and helpful tips to get your new feline friendship off to a good start, and hopefully on their way to becoming best buddies for the rest of their lives! (We use the word “cat” below, but you can substitute “kitten” if that applies.)

Generally it’s believed the easiest introduction is when the new cat is younger, smaller, and of the opposite sex, but it really depends on the personalities and experiences of the felines involved. Neutering/spaying of all cats to be introduced is essential, ideally 2-4 weeks before the introduction, so they are fully recovered and hormones have had time to subside.


Confine the new cat to one room with a litterbox, food, water, and a bed. Feed your current cat(s) and the newcomer on either side of the door to this room. Don’t put the food so close to the door that the cats are too upset by each other to eat. This will help to start things out on the right foot by associating something enjoyable (eating!) with each others’ presence. Gradually move the dishes closer to the door until the cats can eat calmly directly on either side.

If you have adopted the new cat from an environment (like a shelter or the street) where they could have been exposed to illnesses, follow the recommendations of your vet for the duration of this isolation.  Often your vet will test for FeLV and FIV, and then recommend isolation for 7 to 10 days.  That may seem like a long time, but in addition to keeping your resident cat healthy, the new cat will have a chance to get adjusted to his/her environment’s sounds and smells, improving the chances that the first face-to-face introduction with your resident cat(s) will go well.



After your new cat’s isolation period is over and your new cat is healthy, you can take these next steps, in order. Advance to the next step only after all cats are OK with each other during each step.

  1. Switch sleeping blankets between the new cat and resident cats so they have a chance to become accustomed to each other’s scent. Also put the scented blankets underneath the food dishes.
  2. Use two doorstops to prop open the door just enough to allow the cats to see each other (an inch opening) but not get out, and repeat the feeding nearby process.
  3. Put the new cat in a secure cat carrier, and open the door so the resident cat can come in and sniff all around the new cat’s room and new cat in carrier.
  4. Confine resident cats in another room, and let the new cat explore the rest of the house. This switch provides another way for the cats to have experience with each other’s scent without a face to face meeting. It also allows the newcomer to become familiar with his/her new surroundings without being frightened by other animals.



The moment you’ve been waiting for — the cats’ first full meeting! Open the isolation room door and calmly observe. You may want to have a water squirt bottle in one hand, and a blanket in the other, just in case you need to intervene in a sudden attack. Playing calming music or talking in a calm friendly voice to the cats will help YOU to feel less stressed, which will help the cats too!

If your cats like treats, give them lots of treats along with verbal praise. Some cats do best if distracted with their favorite toys, so they are not focusing too intently on each other.

A little hissing, puffy tails, and even a little growling is normal, but should be minimal if you have taken the time to follow the steps above. Don’t give them the opportunity to intensify. You are trying to avoid the cats associating each other’s presence with fearful or aggressive behavior. A bad first impression can be difficult to change.

If either cat becomes fearful or aggressive, like escalating or constant hissing or growling, or if there is any stalking (like they are hunting prey), cornering, swatting, or big posturing displays of arched backs and fur puffed out like Halloween cats — separate the cats back into their own spaces immediately. If it was dramatic, you may have to take a step or two back (back to feeding on either side of propped open door for example) and slowly move forward when they’ve calmed back down. If it was just a hissing match, wait a few hours and try another few minutes.

When it is going well, let them spend up to 10 minutes together – less time is fine too! Then separate back into their own spaces. It can be super tempting to let them stay out if it is going well, but it is much better not to over-face them and have the first meeting end badly.




It is much better to introduce cats to each other gradually. Say you did five minutes the first day, once in the morning and once at night. Day two, if they are doing well (just minor hissing or ignoring each other) your sessions might increase to three sessions of 10 minutes each.

Sometimes it seems to be going well, and then there’s a spat. Cats can make lots of noise and roll around quite dramatically without either cat being injured. If small spats do occur between the cats, do not attempt to bodily intervene to separate the cats. Instead, use a spray bottle to squirt water on the cats in order to separate them — if that doesn’t do it, trying tossing a blanket over one of them, and quickly corralling the other cat of the room. Give them both a chance to calm down before re-introducing them to each other – like a day or more.



  • keep the second litterbox in the isolation room even after the cats are out together – if you want to move it, do so gradually a few feet at a time to the new location
  • clean all the boxes more frequently
  • increase both cats playtime and exercise – helps expend energy to keep cats calmer
  • make sure that none of the cats is being “ambushed” by another while trying to use the litter box
  • keep the resident cat’s schedule as close as possible to what it was before the newcomers appearance.
  • calming products like Rescue Remedy and Feliway hormone sprays or plugins (available at pet supply stores) can help to de-stress cats

While cats can take weeks to months to get adjusted, most cats can learn to co-habitate peacefully, if not become the best of friends!

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