Instructions
Gradually Introducing Cats
Choose a cat that seems like a good fit with your other pet or pets. While you can't say with certainty whether two cats will get along, you can help minimize the chances of conflict by adopting a cat with a similar energy level and personality as your other cat(s). If you have an active, healthy adult cat, a kitten of the opposite sex may be a good match. However, if your cat is elderly, can be grouchy or dislikes being disturbed, it might not appreciate a kitten's energy. If you're getting your new cat from a shelter or rescue, ask how it gets along with other cats and what traits might affect its assimilation into your home.
Set up a space for the new cat. This should be separate from the area where your other cat or cats live. Provide water, food, a litter box, some toys and several places where the cat can hide. Spend at least an hour a day with each of your cats, playing, petting and checking for indications of stress. These may include not eating, excessive hiding or hostility.
Switch the cats' spaces so they can get used to each others' scents. Wait at least two days after bringing the new cat home before doing this, longer if the cats seem stressed or stop eating. They should be comfortable and relaxed before you make the change. This means they may vocalize through the door but should not be hissing or growling. They may also reach paws beneath the door to try to get acquainted. If any of the cats seem intimidated or retreat from this behavior, they're not ready to meet.
Allow the cats to sniff each other and exchange vocalizations through a closed door. A screen door, if you have one between rooms, may work especially well in helping the cats become acquainted without causing excessive stress or fights.
Move the cats into the same room when they all seem relaxed and comfortable communicating through the door. Place them at opposite sides of the room and give each several toys and treats. Separate them if they show any signs of stress or aggression, and give them more time to become acquainted from opposite sides of a closed door before trying to reintroduce them face to face.
How to Introduce House Cats Together
When you bring a new cat into a home where one or more cats already live, it's important to introduce them slowly and carefully to minimize conflict. Cats usually take longer to adjust to and accept each other than dogs do. Allow the cats to become familiar with each others' smells and to start getting acquainted through a door or screen before you place them in physical proximity.