An outbreak of pox disease in Carnivora of the family Felidae occurred in the Moscow Zoo. Two forms of the disease were found: (1) fatal, fulminant pulmonary without skin lesions and (2) dermal with rash. The severity of the dermal form varied from subclinical to lethal. The pulmonary form was characterized by pneumonia and exudative pleuritis, and large concentrations of virus were observed in the lungs and exudate. In addition to Carnivora of the family Felidae, two giant anteaters had a severe form of the disease (dermal with hemorrhages) and died. The agent of the outbreak appeared to be very closely related to cowpox virus; however, pocks developed at a lower temperature than do those that result from infection with cowpox virus. Strains isolated from sick animals were identical to the virus previously isolated from an outbreak of pox among elephants and okapi. The most probable sources of infection were rats that were fed to some of the animals. During the outbreak, a female attendant at the zoo became infected.