September 2, 2023

Adopt-a-Pet.com Blog How to Introduce Cats: Introducing a New Cat or Kitten to Your Cats

Ivan Ozerov / Stocksy
If you’re a cat parent who is considering bringing a new kitten into the home, or if you’ve already adopted one, you’re likely wondering how best to introduce your resident cat to their new family member. Introducing a new kitten to a resident cat can be challenging, and, depending on the cats’ ages and personalities, it may take days or months to do so successfully. However, it’s important to introduce cats slowly and carefully to prevent aggression or fighting.

Below are some guidelines and helpful tips to get your new feline family members off to a good start and hopefully on their way to becoming best buddies for the rest of their lives.

How to Choose a New Kitten to Bring Home

If you have yet to adopt a new kitten, keep in mind that most cat experts recommend introducing a new cat who matches the resident cat’s energy level, size, and personality. Bringing home a kitten if you have a senior or low-key adult cat can be like asking a grandparent to babysit a toddler 24/7: The kitten will be sad not having a playmate, and the older cat will be stressed by the kitten asking to play constantly.

In fact, kittens are much happier in pairs, so if you’re set on adopting a kitten, consider adopting two. It may seem overwhelming, but it could actually be the best solution for everyone, as the kittens will play with each other and leave your adult cat to do their own thing. Adopting two kittens will also help them avoid Single Kitten Syndrome.

Some cat experts also believe that gender plays a small role in how two cats will get along and suggest two males or a male/female match work best. Neutering and spaying all cats, ideally two to four weeks before the introduction, is also essential so they are fully recovered.

No matter which new kitten or cat you bring home, though, it’s important to follow the steps below to successfully introduce them to your resident cat.

How to Introduce a New Cat to Your Cat

Step One: Isolation

Confine the new cat to one room with a litter box, 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.

You can also consider using the crate method, which essentially replaces a separate room with a very large crate, which is especially helpful if you live in a space that does not have an adequate separate room.

If you have adopted the new cat from an environment where they could have been exposed to illnesses, such as a shelter or the street, follow your vet’s recommendations for the duration of this isolation. Often your vet will test for FeLV and FIV and then recommend isolation for seven to 10 days. That may seem like a long time, but it will not only keep your resident cat healthy but also give your new cat a chance to get adjusted to their environment’s sounds and smells, improving the chances that the first face-to-face introduction with your resident cat(s) will go well.

Step Two: Scent / Sign Intro

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

Switch sleeping blankets between the new cat and resident cat(s) so they can become accustomed to each other’s scent. Also, put the scented blankets underneath the food dishes.
Use two doorstops to prop open the door just enough to allow the cats to see each other but not get out and repeat the feeding process.
Put the new cat in a secure cat carrier, and open the door so the resident cat can come in and sniff around the new cat’s room while the cat is in the carrier.
Confine resident cats in another room and let the new cat explore the rest of the house. This switch also allows the cats to experience each other’s scent without a face-to-face meeting. It also allows the newcomer to become familiar with their new surroundings without being frightened by other animals.

Step Three: First Meeting

Open the isolation room door, let your resident cat enter, and calmly observe. Playing calming music or talking in a calm, friendly voice to the cats may help you 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.

When the cats are together, keep an eye out for the following warning signs:

Hissing, puffy tails, and growling: A little bit of this behavior is normal but should be minimal if you have taken the time to follow the steps above. Don’t give your cats 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.
Fearful or aggressive reactions: If either cat escalates their behavior to 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, separate the cats back into their own spaces immediately. If it was just a hissing match, wait a few hours and try another face-to-face meeting for a few minutes. If the aggression seemed serious, you may have to take a step or two back in the introduction process.

If the meeting is going well, let the cats spend up to 10 minutes together (although less time is fine, too). Then separate them back into their own spaces. Letting them stay if it is going well can be tempting, but it is much better not to push it and have the first meeting end badly.

Laura Stolfi / Stocksy

How can I prevent aggressive behavior during introductions?

The above process of slowly introducing your resident cat to a new cat will do a lot to help reduce aggression. When you reach the step of a face-to-face introduction, you may want to have a water squirt bottle in one hand and a blanket in the other in case you need to intervene in a sudden attack. Supervise their interactions closely at all times, and be patient. It may take some time for the two cats to become friends, but most cats can learn to live together peacefully with time and patience.

Step Four: Slowly Increase Time Together

If your cats successfully spend up to 10 minutes together, you can increase their time together. For example, your sessions might increase to two sessions of 10 minutes each on day two.

Continue to observe your cats vigilantly, however, because sometimes a meeting will seem to be going well, and then there’s a spat. If a small spat occurs between the cats, do not attempt to physically intervene; cats can make lots of noise and roll around quite dramatically without either cat being injured. Instead, use a spray bottle to squirt water on the cats to separate them. If that doesn’t do it, try tossing a blanket over one of them and quickly corralling the other cat out of the room. Give them both a chance to calm down for a day or more before re-introducing them to each other.

When can I consider the introduction process successful?

You can consider the introduction process successful when you observe signs showing that the cats are getting along, such as greeting each other by sniffing or touching noses, headbutting or rubbing against each other, grooming each other, and, of course, snuggling and sleeping together.

More New Cat Tips

Once you’ve made it through the introduction process, there are still some things you can do to ensure your cats continue to get along, including:

Keep the second litter box in the isolation room even after the cats are out together. Make sure that none of the cats are being “ambushed” by another while trying to use the litter box.
If you want to move the second litter box, do so gradually, a few feet at a time, to the new location.
Clean all litter boxes more frequently.
Increase the amount of playtime and exercise both cats are getting to help expend their energy and keep them calm.
Keep the resident cat’s schedule as close as possible to what it was before the newcomer’s appearance.
Try using calming products to help de-stress cats who exhibit signs of stress.

FAQ (People Also Ask)

How long should I wait to introduce my cat to a new kitten?

Introducing a new kitten to a resident cat can be challenging, and, depending on the cats’ ages and personalities, it may take days or months to do so successfully. Follow the above steps for a slow introduction.

What if the cats still aren’t getting along after extended efforts?

If your cats still aren’t getting along after extended efforts, you should consider consulting a veterinarian to determine if underlying medical issues are at play, and/or a certified cat behaviorist. If the issue truly cannot be resolved, you might consider rehoming your cat via Rehome by Adopt a Pet.

What are the warning signs when introducing cats?

Warning signs when introducing cats include hissing, puffy tails, and growling. A little of this behavior is okay, but if it escalates to 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, the cats should be separated.