Cat is pooping on the floor. Why? When you find cat’s poo on the floor where it doesn’t belong, your first impulse is to run out and buy an automatic sifting litter box. You might even convince yourself that it isn’t a big deal — after all, your neighbor’s cat never uses his box. However, just because he doesn’t care about his box doesn’t mean that your cat is satisfied with his bathroom behavior. There are several common reasons for this troublesome issue — some of them far more serious than others.