I have an 11 year old female domestic short hair cat. She has always been a very good cat non aggressive. My son brought in a 5 week old kitten and the 11 year old is always hissing when the kitten gets too close. We put them together only with supervision because I am not sure if my older cat will attack this small kitten. How can I make this transition as easy as possible for my older cat so she will accept the kitten. I am just afraid she will hurt the kitten if I left them to themsleves.

It should take a couple of months for the cat to accept the kitten. Never leave them alone. It will probably easier if the kitten is a male. While they may never be friends the older one should learn to accept the kitten.

The kitten is going to need a lot of play time with you humans. Be prepared:)

Yep your doing fine its more the less a jealous problem keep it up get them together as much as you can when your home, hopefully mr. grumpy will come out of it and they will both be able to play. Like said in the above they may not be friends but they can at least accept each other.

And never show favoritism like making the older cat think the kitten is more important to you. I have found cats to be very biased, if a strange cat looks like a cat they already know, maybe the same color or pattern they are more accepting. Once had a new kitten that ran the roost too, all the older cats cowered at the top of the stairs in fear of the tiny little fellow who walked around with a swagger. Had another orange tabby, could make a golden retreiver decide to cross the street to avoid him, he was so intimidating. But he was not aggressive, just gave them a look that would make a Marine think twice. So one will be in charge either way. You just referee and send them to their rooms without dessert.

I just brought a new cat into the house myself. (Well, it's been about 3 months now.) This is a transition you always must go through, because cats are territorial and don't like new cats coming in. Hopefully it will make you more comfortable to know that this is normal. And the older the cat, sometimes the harder it is to accept a new one.

Fortunately my older cat spent a good part of his life with another cat, but he'd had 2 & 1/2 years by himself and got spoiled by it. But cats weren't new to him. He also is an extremely curious cat and his curiosity finally won out over his anger. But still, three months later there's sometimes some growling and hissing going on. The younger one usually is growling, while the older one stands guard over her, presumably establishing his predominance.

One added issue you have is a young kitten with a lot of energy, who will want to play, combined with a cat who probably is just sleeping a lot these days and may not want to play. The older one may just start playing eventually (and get some exercise). Or this may continue to be a problem, meaning spend time playing with the kitten and have plenty of toys, as the older one may not want bothered.

It's already been said not to leave them alone together, until you know they're OK together. But when you're there to supervise, let them do whatever they want, unless one could seriously get hurt. They need to establish their own territories and decide who is boss -- they will do this for themselves. So just ignore the hissing and growling, and only jump in if a serious injury could happen. New behaviors may happen, but older ones could come back. (Like my older cat always sits on the footstool of my recliner with me. When I got the new cat, she would jump up and sit on my lap, and the older cat wouldn't get on the chair at all, but sit on the floor and watch. But after several weeks, he finally started getting on the footstool again and is back to his normal behaviors.)

Give the older cat plenty of attention and affection, so that she knows she is still loved. You can't help but give the kitten attention also, but she needs to know you still love her.

I have had my kitten for 10 months and my cat still hisses and attacks it!

I also have a question I have 7mnth old cat we have had since she was 12 weeks she is great cuddly cat we just bought last night another kitten which is 14 weeks at first the older cat hissed and the new kitten didn't a couplen hours later the hissin stopped and she wanted to rough play with the new kitten now the new kitten growls and hisses only when rough play the older cat will bat her in the head occasionaly but seems harmless is this OK and since they seem to be OK when I leave can I keep them together or separate them