Bilateral conjunctivitis and episcleritis were identified in an adult European starling ( Sturnus vulgaris ). A novel mycoplasma species, Mycoplasma sturni , was isolated in pure culture from the conjunctiva of both eyes. The clinical presentation was similar to that of conjunctivitis in house finches ( Carpodacus mexicanus ) caused by Mycoplasma gallisepticum . However, the histologic lesions were distinct, by the presence of ulceration and epithelial hyperplasia and lacking a lymphoplasmacytic infiltration. Mycoplasma sturni ferments glucose, does not hemadsorb or hemagglutinate chicken erythrocytes, and grows rapidly at 37 C in comparison to other Mycoplasma spp. The role of M. sturni in conjunctivitis in other passerine species is presently unknown.