Onchocerca raillieti sp. n. (Filarioidea), from the domestic donkey (Equus asinus) in Africa, is described. The species is compared to O. bohmi (Supperer, 1953) n.comb, O. reticulata Diesing, 1841, O. cervicalis Railliet et Henry, 1910, O. flexuosa (Wed), 1856) and O. armillata Railliet et Henry, 1909 and can be differentiated by numerous characters of which the most important are the anterior region of the female (which is straight and slender, 6 to 8 cm long, and bears longitudinal striae) and the 10 symmetrically arranged pairs of caudal papillae. O. raillieti seems to be a primitive species by several characters (caudal papillae, cervical papillae, oesophagus, vulva and cuticle.)
