Here are some tips on introducing the new addition to your other cats. 

Introducing a new cat to a household with previously existing cats can be troublesome sometimes. Cats have very tight-knit societies and they often resist abrupt changes in their society. A new cat coming into the house is exactly what the established cat would not appreciate.

Having said that, some cats are introduced to each other with very little aggression or problems. I want to give you some advice on new cat introductions to make the process go more smoothly and hopefully avoid difficulties. When a new cat is to be introduced into the house, they should not be simply put into the same room as the existing cat and left alone. This could result in a large fight and a subsequent trip to the nearest vet clinic! Cats need to be introduced slowly. Remember that juvenile cat and kittens are more readily accepted than older cats, but even older cats can learn to get along.

Here are the steps for cat introductions that seem to work the best.

  1. Bring the new cat into the house and isolate it in one room of the house with the door closed at all times. This will allow the existing cat to get used to the new cat’s smell (and vice-versa) before they actually get to meet. The cats may even put their paws under the door and bat at each other. That’s ok.
  2. Swap the cat’s territories. Once the new cat has spent a day in the room alone, then put the resident cat in that room and let the new cat out into the house. This will allow for even more opportunity to acclimate to the new smells and helps to prevent territoriality as it pertains to that one room.
  3. Let the cats see each other without touching. This can be done in many ways. You can use a cat carrier and alternate which cat is in the carrier each time you allow a meeting. You can use a screen door to separate the cats, use double baby-gates (one on top of the other) to create a see-through wall, or you can fix the solid door with a rope and stick to keep it partially open, but not open wide enough for either cat to squeeze through.
  4. Introduce the cats while you are home to supervise. Do not move to this step until the cats seem comfortable with each other as described in step 3. If the cats are growling or hissing, wait until their aggression has subsided to try to introduce them. Once they appear to be interested in meeting, or are ignoring each other, let them out together and allow them to sniff noses. If you are at all concerned that they may fight, then put them both on long leashes so that you can separate them if they do try to fight. The best way to leash them is to use a harness, but you can also use a collar and attach a light leash.

In most cases this step-by-step approach will prevent fights and litter box problems when a new cat is introduced. Remember to also get an extra litter box for the new cat so there is plenty of litter to go around! The rule of thumb is one litter box per cat, plus one. Enjoy your new extended family!

For more information and a different introduction protocol, please visit:

Dr. Amy Hellard

West Chester Veterinary Care