Abstract: A battery-powered ventilated litter box having a litter box assembly with a litter tray and a removable lid enclosure with a door opening that provides pet access to an inner space. A fan assembly includes a housing that is attached to the lid enclosure and which forms an air conduit through the lid enclosure. The housing has an air exhaust and an air intake and a fan assembly having a fan that draws air from the inner space into the air intake. A filter element is disposed within the fan assembly. The fan expels air from the air exhaust. The litter box assembly includes louvers, preferably on the sides of the litter box assembly and a downwardly extending lower rim that mates with the litter box. The fan includes a fan motor having a vertically orientated shaft. The filter element is preferably a HEPA filter.