Introducing Kitten to Adult Cat: Week 1

Bringing home a new kitten is very exciting, but to your adult cat it can be a stressful experience.

The general advised way of introducing a new kitten to adult cat is first by smell, then scent then sight, with a lot of patience in between. This transition can take anywhere from a day to days, weeks or even months. How exactly you do this will depend on your home setup.  I will share exactly how the first week went for us.

First day home:

I put the carrier directly in our bedroom with some toys, litter box and food. Cornelius saw us carry in the carrier and was already curious by the sight and smells. She did not want to come out of the carrier for the first 20 minutes and when she did she hide anywhere she could in the room. I left her alone and was in and out of the room the rest of the day.

After a few hours she was exploring and playing everywhere in the room.  Cornelius spent most of the time at the door. I then put the empty carrier outside for Cornelius to smell and explore. I didn’t do any introductions the first night but Cornelius was curious enough with us going in and out of the room all day. Throughout the day we would put her in the litter box.

First night home:

I slept in the living room with Cornelius because he is a bit more attached to me. My husband slept in our room with the new kitten. To me it was important for me to sleep with Cornelius so he wouldn’t feel excluded as normally he always sleeps with us in our room. If I would not have slept in the living room with him I know he would have been scratching at the door and meowing.

Litter Box

A1 midnight my husband witnessed the kitten pee in a potted plant in the bedroom. We then removed the plant. I should have thought about this before, but I forgot how little she was and didn’t realize the plant was big enough for her to use a toilet. Which brings me to the most important tip. Set-up the room for your cat to succeed: clean and tidy the room, put away clothes, take away flush rugs, plants or anything else that could be mistaken for a litter box.

Day 2:

The first morning she successfully peed in the litter box. And I thought we were set. A few times that day we put the carrier with her inside in the living room for Cornelius to come and smell and see without being able to touch her. There was a lot of staring and a few hiss from each cat. But overall Cornelius seemed more curious than aggressive. Hissing is a normal response from both cats and should be expected. I did this at least 5 separate times through out the day without allowing the kitten out of the carrier. We were in and out of the home all day so when we left we put her back in the bedroom.

Litter Box

We then came home to pee on the bed :-( The first time I have ever experienced a cat pee outside the litter box let alone on the bed. I was horrified. I stripped the bed and cleaned everything then put a shower curtain over the bed. We continued to put her back in the litter box and she peed in the box right in front of me. So again I thought we were fine.

That night we did the same sleeping arrangement as the first night. No accidents. Early in the morning she used the box again.

introduce kitten to adult cat

Day 3:

We brought out the carrier to the living room and opened it so she could come out if she wanted. She slowly came out and showed no fear towards Cornelius. Instead she ran to him excitedly. There was some more hissing but Cornelius mostly backed away and was very unsure of her. She then curiously explored the living room. I was a little concerned by the way Cornelius was following/watching almost stalking her. I was afraid he was confusing her as prey and would pounce on her. But once she would hiss or go on the offense instead of defense that would lessen his fixation. We did a couple controlled meetings like this throughout the day. I wasn’t comfortable allowing them to touch and be together unsupervised yet. Same sleeping arrangement in separate rooms as the night before.

Litter Box

Then when we were gone she pooped on the bed (on the shower curtain). :-( I quickly decided her safe room would now be the bathroom, not our bedroom.

Safe room for kitten

Items in safe room: Cat Ball® cat bed, Bergan Scratcher Cat Toy, litter box, food and water. Plus a couple other mice and balls to play with.

Day 4:

That morning we started the controlled interaction but allowed them to be closer and have direct contact. I was a little nervous but overall it went well. I was happy to see the kitten be assertive at times and set limits by growling, standing large or hissing. This helped Cornelius realize this was not prey and there were limits on how he could interact. 80% of the day they were together. I separated them at meal times because they are eating different foods. I still fed the kitten in the bathroom and would leave her in there for about 40 minutes after she ate. She would always go to the toilet at this time and no more accidents! If I left home I would also put her back in the bathroom.

Day 5:

This was the first day they lived together all day and night. There was a lot of playing and chasing all day. I was so happy to see them getting along. There were a few times were I intervened because I thought they were playing a bit to hard. But overall everyone was happy.

Day 6-7:

We continued to live together day and night. I still put her in the bathroom during and after meals. Several times I witnessed her going into the litter box on her own and using it. I was mindful of when she was in the box to not let Cornelius approach her. Still no accidents!

Introducing cats

So that’s week 1. I go back to work on day 9 so stay tuned to see how this progresses.




  1. September 13, 2015 / 2:59 am

    This is Kiril, from The Opinionated Pussycat!

    Thank you for stopping by to see our new baby….and inviting me to read about how you handled a similar situation….

    Living in a studio apartment limits where I can stick the newbie while I’m at work, so the bathroom has had to do….For a month old she quickly caught on to the littler box within 2 days….When I finially let her out to roam and meet the other older cats this made for an interesting, mostly poditive first week.

    Being so tiny I leave her in the bathroom when I am not home…

    We are now into week 2 as of today.

    • September 13, 2015 / 6:11 am

      That’s great they are adjusting so well. One month old is soooo tiny, I think you are right by leaving her in the bathroom when you are gone. At one month they are so easily hurt and also big risk takers. Best of luck with your little one!

  2. June 7, 2015 / 8:53 pm

    Don’t worry about them playing too “hard” ; Cornelius is just bringing her up in a “cat-mode”. We’re so glad they go along so well. Food and litter box in the same small room could maybe explain the wee and poo accidents. We’re looking forward to knowing her name ! Purrs

  3. June 7, 2015 / 6:18 pm

    This day-by-day journal documenting the new kitten is a good guide for anyone who is preparing to introduce a new cat to the house.