Abstract: A cat litter box having a right angle rectangular prismatic configuration formed from a rigid cardboard base including a bottom and upstanding side walls joined to the bottom at fold lines and an impermeable laminar covering of plastic sheet material over the opposite surfaces of the 5 cardboard base. The covering is slightly longer and wider than the base and the sheets are joined at the marginal regions beyond the edges of the base. The panels defining the walls and attached to the bottom define open areas between adjacent walls. When the walls are folded up, the excess covering plastic material is folded over and is adhered to the walls, defining closure flaps and holding the walls upright.