Abstract: A cat litter box system including a tray which may have inwardly canted edges and a waterproof bottom. Inserted in the tray is at least one orificed filter sheet, and preferably several, having some type of corner or edge lifting means. Also desirably provided is a filter protector comprising a mat having upward extending protrusions disposed in register with the filter sheet orifices to pass through the latter and protect the filter sheets from damage by the clawing of the cat through litter material which is deposited in the tray over the filter sheets and the filter protector, where the latter is also used. Deodorizing strips, capsules and/or filter protector tips may also be provided.