A litter box and sifting system having a cat door that is installed on the interior wall of a building and a litter box assembly located on the exterior side of the building. The litter box is accessed through a cat door and an adjustable tunnel. At the bottom of the litter box are interchangeable tray assemblies containing litter. The litter can be selectively sifting through fixed screens and removable sliding panels. The litter box enclosure includes a fan to assist ventilation through louvers, an interior light, a rechargeable battery for powering the fan and light, and a solar cell to recharge the battery.
