Question:

What should I do first to introduce my new cat to my old cat?

Introducing New Pets to Home

Introduction
Cats are territorial creatures. While they seem laid-back, relaxed and easygoing, in reality, when another cat that brings in strange smells comes through the front door, the resident cat will raise his hackles, and begin spitting and hissing. This is natural and it can be dangerous for both the resident cat, called RC and the newcomer, known as NC.

Slow and Steady
You will get the best results when you take this introduction slowly and carefully. Because RC will be angry, especially when he smells the scent of NC, have a safe room ready ahead of time. You will use this room to house NC for several days so she can get used to the noises, sounds and smells of your home. The slow and steady introduction also helps RC get reconciled to the reality of the new kitty in your household.

Equip the safe room with food and water bowls, a litter box, fresh litter, toys, food, water and a scratching post. Bring NC in and keep her inside her carrier. Once you get into her safe room, close the door tightly and let NC out of her carrier. She will slide under a piece of furniture, where she will feel safer. Let her stay there for as long as necessary. As she wanders around her safe room, she will deposit her scent on furniture, the floor and carpeting. RC, as he sniffs at the closed door, will pick up on her scent. For the first week, this should be the extent of their contact with each other.

Maintain Familiar Routines
Feed RC and NC at the times they are used to. This may mean feeding the new kitty at a later or earlier time than RC. If so, gradually shift the feeding time of NC to one that is closer to the feeding time of RC.

Continue cleaning both cats litter boxes at least twice a day. Continue your play and cuddling routine with RC and add some play time for NC. Use the clothing you wore to play with both cats as part of your socialization work. Take that T-shirt off that RC rubbed and rub it over NC. Do the same with the jeans that NC sat on. Rub them over RC, so both cats cat accustomed to each others scents.

As you go about your daily routines, expect RC to begin sitting right outside the safe room as he waits for NC to show herself. He may growl and hiss at the door; he may hide; he may mark territory he believes to be his. Do not get mad at RC. He is only doing what is natural for him. Instead, plug in a pheromone diffuser so he and NC both begin to calm down

Be Watchful and Wary
Take a long piece of string and tie two balls to each end. Stick one ball in the safe room and allow NC to play with it. Place the other ball just outside the closed door of the safe room and allow RC to play with it. Eventually, they will be playing with each other.

Find a heavy object and use that to wedge the safe room door open about one inch. Allow both cats to get glimpses of each other and expect growling, spitting and hissing.

Switch both kitties around. Put RC in the safe room for a day and allow NC to have full run of your house. Switch their toys, litter boxes, food and water bowls. Begin doing this switching more frequently so each cat can get used to the scent of the other one.

Introduction Day
Finally, the big day is here. Put NC into her carrier and open the safe room door. Allow RC to come in and sniff at her. Watch their interactions for clues. They will posture and hiss. If any meeting looks like a confrontation could develop, plan to continue these controlled meetings for several more days.

Once there is no tension or aggression, let NC out of her carrier. Stay in the room while the two cats are getting to know each other. In fact, you and your family should monitor all interactions until you definitely know that neither cat will become aggressive. When you have to leave, shut NC up in the safe room with her supplies.

If the cats regress in their introductions, place NC back in the safe room and start the introduction process over from the beginning.