A paramyxovirus related to parainfluenza 2 (PI₂) virus was recovered from the lungs of two dead ottoman vipers from a zoological collection. Snakes of other species in the collection were unaffected. Histologic examination of the vipers' lungs revealed interstitial pneumonia, and degeneration and hyperplasia of bronchial and atrial epithelia. Scattered vacuoles, some of which contain eosinophilic inclusion bodies, were seen in the cytoplasm of several cells of affected epithelial tissues. The virus recovered from pulmonary tissues of the snakes replicated optimally at 30 C in a variety of cell cultures and hemagglutinated chicken erythrocytes. Viral hemagglutination was inhibited by PI₂ virus antiserum, but not by antisera to PI₁, PI₃, respiratory syncytial, and canine distemper viruses. Indirect immunofluorescence with PI₂ antiserum specifically stained inclusions in the epithelial cells of respiratory tissues and infected cell cultures.