A pet litter containment and cleaning system and methods of using a pet litter containment and cleaning system are described. The pet litter system comprises a pan module and removably attached processor module. Soiled pet litter is conveniently processed by rotating a system of the invention, screening and separating soiled litter from clean litter. Pet waste and soiled litter are collected in bags which may be discarded when full. Systems of the invention may be used with both absorbent and nonabsorbent litters. Systems of the invention minimize human contact with soiled pet litter and pet waste and simplify the care of domestic pets.