Abstract: A litter box for separating pet waste from litter material includes a housing having a front panel connected to a rear panel through a pair of side panels extending therebetween, and top and bottom panels extending between the front, rear and side panels to form an interior space for retaining litter and pet waste. The front panel includes an access opening such that a pet can enter into and exit from the interior space. A collection screen is removably mounted in the housing. The collection screen has a bottom wall extending at least substantially between the side panels and the top and bottom panels. The bottom wall includes openings that are sized to permit passage of clean litter material therethrough while preventing passage of pet waste when the litter box is rotated from an upright position where the bottom wall is oriented substantially vertically to a tipped position where the bottom wall is oriented substantially horizontally.