Why does my cat refuse to use the litter box?

I have two cats, Sabre and Jake, brothers and Siamese-Maine Coon mix. Jake has no problem using the litter box, but Sabre will sometimes refuse to, even if it's completely clean. He'll protest by urinating on the wall, which results in my mother locking him in the bathroom with the litter box until he uses it. We've tried cleaning the litter more frequently and even changing it, but to no avail. This is beginning to happen more often, and my mother is considering giving him away if he continues this behavior. Is there anything we can do to stop this behavior?

Unknown

Sabre is not protesting his litterbox, he is spraying or urine marking. This is a territorial behavior common in cats that have not been neutered or spayed. If you have not done this, then neutering Sabre should fix this behavior. Notice I said should, as it is not a cure and there are many cats that still spray after being fixed. These cats are easily set off by environmental stressors such as a new family member or the appearance of a new cat. There could be one outside lurking. Try to locate the area where he's been urinating. Look for any signs of household changes. If you notice any, put them back the way they were if you can. For good measure you can try the Feliway hormone available at www.catfaeries.com There are also clean up agents for your mom there to get that smell off of her walls. I can imagine it isn't helping her decision right now. We don't want that! Purrs