Introducing a New Cat to Your Cat

You likely realize that first impressions count when meeting someone new. The same holds true for cats. A botched introduction could lead to a cool relationship, or worse, between your cats. Allowing each cat to gradually acclimate to the change is more likely to lead to success.


Set up the new cat in a room by himself. He should be completely separated from your first cat for about 7 days. This allows the cats to get used to each other’s scent without needing to confront the other. We recommend using Comfort Zone® with Feliway® diffusers or spray during this separation, as well as the initial stages of the introduction. The Feliway® pheromone helps to reduce anxiety during times of change.

While the cats are separated, encourage positive associations by feeding treats or canned food to them near the door. You can also swap bedding every couple of days so they can further explore each other’s scent. Some hissing is normal during this stage. Don’t punish the cats for hissing or growling as that can form a negative association about the other cat, as well as you.

Seeing Each Other

Once there has been no hissing for a couple of days, it is time to allow the cats to see each other. If this happens within 7 days of the new cat coming home, you may just open the door and permit the cats to explore. Do not force either cat to see the other. You might want to have some treats handy so they can have a pleasant experience together right away. Their reactions will dictate how much time they spend together. As long as they appear to be relaxed, allow them both out. Again, some hissing when they see each other is normal so don’t be alarmed. Some light swatting isn’t uncommon either. Separate them if the hissing doesn’t die down after 1 or 2 minutes or if there is any sign of threat (swatting with force, chasing, screaming, ears flattened, etc.). Try again when the cats seem to be calm; that could be 20 minutes or even days later.

If it takes more than 7 days for the hissing to stop, or there has been little hissing but your first cat avoids the door to the new cat’s room, things need to go more gradually. Allow the cats to see each other while maintaining a physical barrier. This could entail stacking baby gates in the doorway, opening the door an inch or two and using a door stop or hook-and-eye latch to keep the door open, or putting in a screen door. Continue to feed goodies to the cats on opposite sides of the door. Praise them for being calm when they see each other. Continue until the cats have shown no tension around each other for a couple of days, then open the door and proceed as above.

Regardless of which step you take, introduce them during a time when the cats are calm – perhaps shortly after a meal or play time. You need to be calm, as well. Cats can sense tension; your nervousness could translate to anxiety for them, causing a rocky meeting.

Spending Time Together

The cats will set the schedule for how long this process will take. Some cats will be able to spend hours around each other very quickly, others will only be able to handle minutes at a time. Gradually increase the amount of time they spend around each other while you are home and supervising. Once they are routinely spending 4 or 5 hours together without incident, you should be able to give both cats free run of the home overnight and then when you are away. The average time frame is a couple of weeks but it could take months for the cats to learn to tolerate each other.

Throughout the introduction process you should maintain the litter box and feeding area for the new cat in his room. As long as the cats are getting along after a few weeks of being together you can forgo the extra food and water bowls. The general rule regarding litter boxes is one box per cat, plus one, so it may be advisable that you keep the new cat’s box, but you may be able to move it if you prefer a different location.

The majority of introductions are successful and the cats become friends or, at least, have an agreement to co-exist. However, some cats don’t cope well. Contact our Behavior Helpline to talk with a behaviorist if either of the cats is continually hiding, not eating, eliminating out of the litter box, appearing depressed/lethargic, or behaving aggressively.


Thank you to our partners whose support makes our work possible