New Kitten, Big Trouble. How-to Introduce Your Kitten to Your Adult Cat

It is easy to fall in love with a kitten and bring her home, but how can you tell if your adult cat wants to live with a kitten? Even if your current cat does want to live with a new cat, how do you introduce them so that they don’t fight? Read on to find out how to know if your cat wants to live with another cat and how to make the transition go smoothly.

Feral cats generally live in related groups. When a new adult cat comes into the group, it is common for that cat to be rejected. So, if your cat is aggressive toward your kitten, he may simply be behaving normally. But cats are social creatures so they should in theory appreciate other cats, right? That is true, however, most pet cats have not been exposed to other cats. Either they haven’t seen another cat since adopted except through the window or they don’t know any other cats aside from the ones with which they live. To understand your cat better, put yourself in her paws prints. What if you didn’t know any person except your family members and one day a person who looked different, had lots of energy, and kept jumping out from behind corners to pounce on you moved in? Depending on your personality, you might hide under the bed or get aggressive too!!



What does your cat do when he sees another cat out of the window or through the screen? Does he puff up, howl and hiss? Does he look interested and move forward with his tail up? If your cat reacts with mild aggression to other cats through the window, you are likely to have a more difficult time introducing him to another cat than if he did not. He may not be suited to a multicat household at all. If he is just interested, but is not aggressive it might be easier.

This cat is in a defensive posture. He doesn’t want to meet another cat. ‘t has his front paws folded underneath him and he has his back legs underneath him. Picture courtesy of Katy Cohen.

This cat is aroused. He doesn’t want to meet another cat. His fur is up (piloerection) and his pupils are dilated (activation of the sympathetic nervous system or fight or flight).

This cat is open to friendly interaction. His tail is in the “question mark tail” with the tip curled down, his pupils are of normal size, his ears are forward, but relaxed and his hair is not up (piloerection).


 Before you bring your new kitten home, purchase enough food bowls, water bowls, and resting spots to equal the number of cats that you will have including the kitten. You should have one more litterbox and three times the number toys as cats in your home. In other words, if you have 3 cats in your household, you need a minimum of 4 litterboxes and 9 toys. Make sure that valuable things like food, water, toys and litterboxes are spread out all over the house. Each cat needs a place to  hide and a place to go high up in each shared space. 


Spread resources out by feeding some of the cats in the bathroom, some in the kitchen and some on cat trees for example.


Prepare a room for the kitten before you go to pick her up. It should have a litterbox, toys, resting spots, food and water. Your kitten will probably be separated from your new cat for 1-7 days so make is comfortable.




Put a washcloth in each cat’s area. Swap the unwashed cloths daily. Let each cat investigate the other cat’s environment at least once daily. When each cat can investigate each other under the door without aggression, you can introduce them. You don’t have to rub the washcloth on the kitties. Do you want to have someone’s dirty clothes rubbed on you? Just put the washcloth in the other cat’s area and let them investigate it as they please.



Feliway Multicat is a pheromone analogue which comes in a  diffuser form. This is different than the Feliway or Comfort Zone that you may be used to using. It is special formulated to help bring cats together. Plug one diffuser in for every 600 square feet of space.



Introductions are best done in large spaces while the cats are engaged in a distracting activity such as playing with a large toy, hanging out on the screened porch or eating canned food. Don’t force introductions. Take it slowly and separate the cats for a bit each day for the first 2 weeks until you feel confident that they will get along. If you have tried all of the steps above and your cats are still not getting along, speak to your veterinarian. You can also find a board- certified veterinary behaviorist to help you at



What Are Industry Leaders Saying About Dr. Radosta?

Every once in a while, a veterinary unicorn comes along: competent, confident, compassionate, and a great communicator. Brimming with science and soul. Dr. Lisa Radosta is a true "Jill of all trades," fighting important battles and inspiring future leaders. She has played a big role in making animal behavior important, elevating females in our profession, and showing action steps to make a balance between work and home doable. Equally comfortable in the exam room or coming into people's living room via network TV, Dr. Lisa Radosta fights tirelessly to help pets and people live happier, healthier, fuller lives. I often watch her at the podium, in a board meeting, or in an interview and just think..."you go, girl!

Dr. Marty Becker

Dr. Radosta is exceedingly passionate about each individual animal and understands by helping a pet she is also helping families; her passion is only exceeded by her knowledge to make a difference. Dr. Radosta is also a master communicator, whether it is explaining behavior modification to families desperate for exactly what Dr. Radosta and her team provide to communicating to professional colleagues at veterinary meetings.

Steve Dale, CABC

Every single day Dr. Radosta is making the world a better place for dogs and cats suffering from fear, stress, and anxiety. She's highly regarded by veterinarians and board-certified behaviorists alike and I am honored to have worked alongside her to educate pet parents about the importance of caring for our pet's mental health -- she's my "go-to" for video or blog interviews on behavior topics. I've also been a client of Dr. Radosta's behavior practice and I credit her with opening my eyes back in 2006 to how FAS affects our pets' quality of life. 

Kristen Levine