Yet Another Litter Box Question

Recently, my cat has stopped pooing in his litter box. He will happily wee in it but, instead of using the box for a "number two" he goes on the floor next to the box. My parents have decided it's just "how he is" but I refuse to let it go and I'm here trying to figure out the root of the problem. I mean, it's not even as if he won't go in the box at all or he goes in the dining room. He goes inches away from it.

I assume that there is something wrong with the box. I have a rather large cat so perhaps it is too small for him?

Can anyone help? It's kinda urgent - the smell is starting to get to me =]

it can be a lot of things, the size of the box being one of them
Is it a tiny box?
Also, have you changed his litter lately (I mean the type)?

I know there's a lot more things to consider, and I'm sure one of the more experienced members will guide you towards them.
Good luck!

Always have a health problem checked and eliminated, first. Often this is the only way they know how to tell you they are sick.

If the vet clears him, then we turn detective. Not only how big is the box, but how deep. If they can't dig deep enough to bury, they often give up, thinking, I imagine, "I must not be supposed to bury, since I can't." And they will go on tile, because that way burying doesn't even enter into it!

The cleanliness of the box is always a part of the situation. Cats will more often urinate without covering, so if digging a hole is distasteful, they will continue to use the box, just not for solids.

Another thing that will discourage them from the box is cat litter that is more gravely than sandy. Imagine walking on a gravel road in your bare feet. Unpleasant! So try a softer litter.

Defecating is always going to require more time and effort from them. So defecating outside the box is often a clue to a borderline situation. Something about the box is making them uncomfortable, but they are still trying to use it for something quicker, such as urination.

Hope this helps!

In addition to other suggestions, try two boxes, since some cats prefer to pee in one and poop in the other.