Two South American sea lions, Otaria byronia, imported from South America exhibited multiple raised skin nodules upon arrival in the United States. Histological examination of these nodules revealed the dermis to be infiltrated by a proliferative mass of epithelial cells. Large eosinophilic intracytoplasmic inclusions were present in cells of this mass. Electro microscopic examination of the inclusions demonstrated the characteristic dumbbell-shaped poxvirus virion. A similarity between this case report and a human skin poxvirus condition, molluscum contagiosum, was apparent.