Introducing my cat to a new one

Question
Hi,

My husband and I have a male cat who is 4 yrs. old.  He's very loved, and well taken care of.  He is an outdoor cat, but is allowed in and out whenever he wants... we have a cat window. Our neighbors have abandoned their female cat and she has been spending lots of time on our porch, and is now coming inside. I feel horrible for her and want to adopt her but our older cat, Kramer, is not a fan at all! He hisses and growls, and is very uncomfortable around her. He wants to be out more often than usual, and when he's in he will only go into our room. It has only been 5 days since the female cat has been coming in so I want to make sure that I do this correctly. I've read a lot about keeping cats confined to separate rooms but with them both being out and in, that is not possible. Not to mention, that would upset Kramer even more. What are your suggestions? Thanks!

Answer
Hi Paige, I am surprised the female cat felt that she was welcome and could just walk right in with Kramer giving her such a poor reception !
It is not the best situation because if Kramer gets fed up he may just move off to another neighbours porch and spend his time there. If you are serious about keeping her I would keep her confined in the house. For one thing it will allow you to make sure that she is not carrying anything that Kramer could catch and it will let Kramer feel ok about coming home. She is obviously the dominant one which is to be expected with a female. She will not be hissy or bossy but it is just known between these two cats that she is more confident then him and she is not going to move out because of him hissing at her. You will want to keep her confined until Kramer stops hissing at her through the bottom of her door. Once he feels that he still has some say in the home then you can let her out for short periods of time.. but I would not do it before as it sounds like he is ready to leave!
Teresa