My 2 cats won't let new cat use litter box!

I have 2 cats... 1 male and 1 female, that get along very well. I got a new kitty 2 years ago and the 2 older kitties still pick on the new one, even though she is a lot smaller.

Every time she gets near the litter box they try to scare her out of the box, and I feel like I have to watch constantly to make sure she goes.
Help!!!!

I keep the box really clean and have tried buying new boxes so the other 2 don't think it is just theirs... any advice?

They don't get along like I want them to and I worry they might pick on her when I'm not home. Please help if anyone knows how to cure this problem.

---

My Thoughts:

I'm sorry to hear that your cats are having issues. Sometimes cats just don't get along, and you have to split up the house to accommodate them.

I'm wondering if the new cat was introduced to the other 2 slowly? If not, this can result in problems later, so note that for future household additions.

Is the male neutered? Are the females spayed? This can help reduce aggression problems.

Have you tried Rescue Remedy or Feliway? These may help to reduce stress.

It's possible that splitting them up and isolating your new kitty for a while, and then doing a slow reintroduction might help. But, it's been a long time so it's hard to say.

Some people have observed that cats often "pair up" in multi-cat households and odd numbers of cats result in an "odd man out" situation.

Other than the temporary separation and slow reintroduction, I would suggest taking every opportunity to socialize them... group feeding, group playtime, and group treat time daily. Get them doing enjoyable things together as much as possible.

I hope that helps. Please let us know how things work out and what works for your situation.
-Kurt