The cat litter box has a right-angled rectangular prismatic configuration and it is formed from a template composed of a rigid cardboard base (1) and of an impermeable laminar covering of plastic material (2). The cardboard base (1) defines the bottom and side walls and has fold lines which delimit said zones and allow the assembly to be made up. The laminar cover is composed of two flexible sheets (8,9) with a contour which is slightly greater than that of the cardboard base, which sheets are joined together via their edges and delimit, between each two consecutive walls (4,5) of the cardboard base, a zone which, when the assembly is made up, forms closure flaps.