1. Take your time! Introducing a new cat to your home may take a few weeks.
2. Seclude the newcomer in a private room so he can develop a sense of security and begin to form a bond with you. Give him fresh food and water every day and his own litter box for at least a week, without letting him see the other cat in your household.
3. Make frequent visits to feed, pet and play with your new friend and make sure that you spend time with your resident cat so he does not feel that you are paying more attention to the new addition.
4. Feed your resident cat near the door of the room that the new cat is confined in and gradually move the new cats food dish closer to the inside of the door. This will make them associate each other’s presence with something good, food.
5. Give the newcomer brief moments to explore his new home under your supervision without your other cat around. When your new cat seems comfortable in the rest of your house, you are ready to introduce your cat face-to-face.
6. You must be present when the new cat is revealed to your resident cat. Expect some hostility and hesitation. Since they have learned to associate each other with food, a mealtime introduction is helpful.
7. If the cats become aggressive toward one another, remove the food bowls and confine the new cat to the “safe” room. Wait a few minutes and try again. If the second attempt is just as hostile, separate them again and feed them in separate quarters until they settle down.
8. As the cats become accustomed to each other at feeding time, let them spend more time together after they have finished eating.
9. When things seem to be calm, inch their food dishes closer together. If the cats are comfortable being about three feet from each other at mealtimes, you should be ready to let the new kitty out of confinement.
10. As the cats start to share turf within your home, it is recommended that you have at least one litter box per cat. Use a multi-cat litter such as ARM & HAMMER™ Multi-Cat Strength, which features activated baking soda crystals and a new “odor blocking” technology to provide better odor control and performance for multi-cat households.
Source: Dr. Cookie’s Guide to Living Happily Ever After with Your Cat. New York, NY: St. Martin’s Press, 2002.