Hello. I recommend having an extra litter box per cat in your home. So if you only have one, you should buy a second one. What type of litter do you have? Is your cat’s box open or does it have a cover? Some cats prefer to go to the bathroom in a private space, so a litter box with a cover suits them better. Others prefer open litter boxes. I would vary the type of litter/box you use until you find your cat’s perfect fit. Additionally, for a cat to want to use a litter box, the litter box must be placed in a quiet area of the house, and away from its food and water bowl. It must always be clean too. Sometimes, a cat will stop going in the litter box if it has been stressed for one reason or another. Have you recently moved? Has a new person moved into your home? If so, this could be causing your cat stress, and as a result, causing accidents to happen. You could use a pheromone diffuser (such as Feliway), or a food supplement (such as Zylkene) to reduce his anxiety. Hope this helps! Have a great day.