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Introducing a New Cat Into a Home with a Resident Cat

Why can it be difficult for a new cat to be integrated into a home with a resident cat?

Research has proven that cats are actually social animals that benefit from contact with their own kind. However, cats are also territorial species that primarily live with other cats from their own family. They tend to be intolerant of those outside their family. They prefer a consistent environment rather than one that involves change. This is especially true if the change involves a newcomer to your cat’s well-established territory. Our cats don’t usually get to pick their housemates, and we humans can make mistakes when selecting the appropriate companion.

NOTE: Cats that have lived together for year and are separated for a visit to the veterinarian’s office or for grooming may not recognize each other and react aggressively. Reintroduction using the method below may be necessary.

What helps determine if the cats will learn to live together peacefully?

  • Genetics: Friendly parents are more likely to produce friendly offspring.
  • Early Socialization: Adult cats that experienced positive interactions with other cats when young tend to grow into more social cats.
  • Personality of resident cat. When selecting a new cat, it is important to take into consideration how the cats will interact.
    • Resident cat is laid-back, elderly or frail. – Not usually a good match for a young energetic kitten.
    • Resident cat is rambunctious and zooms all over the house – May be too active if your new cat is quiet or reserved.

What if I have a single cat and want to adopt another one as company?

It is important to carefully consider the personality of both cats and how you will introduce the cats to each other. It may take a great deal of time for cats to learn to get along. Even if your resident cat has lived with other cats, it will take time. In some instances the cats will never become buddies and may just learn to tolerate each other’s presence. In others the cats may never get along.

Patience is the key. Socialized cats, slowly acclimated to each other, are less likely to demonstrate aggressive behavior. Once cats have gotten into a fight, the process can take much longer.

What if I have multiple cats?

Each cat should be introduced separately to the new cat. A cat may tolerate some cats residing in the same home, yet not get along with others. The more cats in the home the greater the possibility of aggression and fighting. The smaller an area is the more likely there will be problems. Cats require space to escape if necessary. If one cat is unable to move out of the way of another one, there could be problems.

What if I adopt two kittens together?

Adopting two kittens at the same time can prove helpful. They can play together, provide company to each other when alone and offer an opportunity for both physical and mental enrichment. The best combination is usually two littermates who have grown up together. But it can be just a successful if you select two younger kittens, preferably between 8-12 weeks of age.

Now that I’ve adopted a second cat, what should I do?

Use the SAFE method for introductions. Remember that each situation is different. Some cats will progress faster than others. DO NOT skip a step or move forward before cats are calm and accepting.

  • Secure area and prepare home for new cat.
  • Allow cats to gradually acclimate to each other’s presence.
  • Face-to-face in carefully controlled setting.
  • Ease cats into direct interactions slowly.


1. Provide new cat with an area to claim as its own such as an inside room, enclosed porch, or similar place

  • Quiet, isolated area
  • Convenient hiding places
  • Easy access to food, water and litter box
  • Add a feline pheromone product (Feliway) in the safe room prior to new cat’s being released. This can be purchased at the Adoption Center Desk at the time of adoption.

2. Prepare rest of home for new cat (and help decrease stress level of resident cat)

  • Add a feline pheromone product (Feliway) throughout the entire home prior
  • Increase number of litter boxes, scratching posts and food stations throughout home.
  • Avoid creating spaces where one cat can trap another
  • Increase space within home by providing vertical perches, walkways and areas for hiding. These can be as elaborate or simple as you want.

3. When you arrive home:

  • Quietly place new cat in his safe room with the door closed.
    • Do not stop to show the resident cat what is in the box or carrier. (Your cat will recognize there is another cat in the room by scent and sound.)
    • New cats in the home should be quarantined from the resident animals for a minimum of seven days
  • Allow the resident cat continued access to the rest of the home


1. Feed cats on opposite side of closed door

2. Place both dishes close to door

3. If one cat refuses food,

  • Move bowl slightly further from door.
  • Place some type of extra tasty treat (tuna, etc.) next to the door in an attempt to develop a positive association

Once cats are eating well:

1. Place a towel under the food and water bowl of both cats. After several days, rotate each towel to other cat’s bowls

2. Rub towel over one cat then take same towel and rub it on other cat. Repeat this several times a day.

3. You may also switch places for each cat. The resident cat will be placed in the new cat’s safe room, while the new cat is allowed to investigate the resident cat’s home range. Caution not to allow cats to see each other. This can be done for 1-2 hours, and then the cats are placed back into their original habitat.


1. They may investigate each other under the door

2. Fasten two toys together with cord or rope and place one end on each side of the door so cats can bat at it.

FACE TO FACE (Never move to next step until both cats are comfortable)

1. Prop the door open 1-2”, placing a door stop on both sides of the door so neither cat can get through.

  • Each cat can then see the other
  • Use toys, food and attention
  • Keep all interactions short

2. Wedge the door open a little farther

  • Continue to use toys, food and attention
  • Interaction times should remain short.

3. Allow cats to view each other through a safe partition.

  • Be prepared to distract cats with food or play.


1. Release new cat into room with resident cat. (keep toys and treats handy)

Desired behavior:

  • Cats may mingle in same room
  • Cats sniff and perhaps even groom each other
  • Cats sniff each other (may even hiss) then walk away

Situation to watch

  • Cats sit and stare at each other (May hear low growling )
    • Block view (use cardboard, sofa cushion, etc.)
    • Distract each cat by:
    • Tossing each cat several favorite, tasty treats toward both cats. Don’t be afraid to use something like Tuna, sardines, you are attempt to entice the cats away from each other.
    • Using toys (best toys for this are often wand-type that encourage play while keeping a safe distance from the cats). Have one for each cat.

The above suggestions will help ensure introductions of our new cat and your resident cat have the best possibility of success. In some instances it can take several months for the cats to settle so don’t become discouraged. The two cats may never become best buddies, but in most cases, can learn to co-exist in peace.

If after all your hard work, things don’t work out remember: Cats that have lived a solitary life at home can be perfectly happy as long as you provide them with their own space, attention, shelter and food.

Please contact your veterinarian if you continue to have problems introducing the cats.

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