We measured seasonal changes in body mass and pathogen exposure in wild Pallas' cats (Felis [Otocolobus] manul) in the Daurian Steppe of Russia in 2010–11. Pallas' cats lost about 30% of body mass over winter. Tests for antibodies to 15 potential pathogens showed that Pallas' cats were exposed to four pathogens. Two of 16 cats had antibodies to Toxoplasma gondii. Two had antibodies to Mycoplasma sp., and one each had antibodies to Influenza A virus and Feline leukemia virus. The percentage of antibody-positive wild Pallas' cats was lower than results reported for other wild felids in the Russian Far East.