We evaluated the habitat selection of 101 den sites used by 21 individual Pallas's cats (Otocolobus manul (Pallas, 1776) = Felis manul Pallas, 1776) in summer, winter, and the maternal period in central Mongolia using generalized linear mixed models. Pallas's cats used rock crevices and marmot burrows as dens for giving birth, raising young, thermoregulation, feeding, mating, and as important cover from predators. Den sites were selected with higher proportions of rocky and ravine habitats in the surroundings, and in winter Pallas's cats avoided the presence of humans. Habitat and structural features suggested that dens were selected to minimize predation risk. Selection of dens in shade in summer and the use of insulated dens of Siberian marmots (Marmota sibirica (Radde, 1862)) in winter indicated that thermal properties may also be important. We contend that dens are a critical habitat for Pallas's cats and the availability of suitable den sites is critical for the conservation of the species. Repeated use of maternal dens suggested they may be a limiting resource. Although marmot dens are unlikely to be limiting at present, over hunting of marmots is likely to reduce burrow availability in the future.