Abstract: The present invention is a cylindrical litter box with a litter pan and a lid, which is removably attached to the litter pan. The litter pan comprises of a body having a circular base, a cylindrical side wall that is joint at its bottom end to the circular base. The cylindrical pan includes an open top that is defined by a peripheral lip. The open top end includes a double brim: an outer brim dedicated to securely support the lid, an inner brim to support a clutch and secure a bag, and a cavity separating the two brims. An especially designed bag that can be rolled open is attached from its open end to the inner brim and lines the pan. The rolled part of the bag is secured inside the cavity in between the inner and outer brims.