Onchoecercal microfilaruia was studied in the course of an epidemiologic investigation of diseases, infections, and general health conditions in a rural village on the Adamaoua Plateau in northern Cameroon. Microfilariae of Onchocerca volvulus were observed in nearly one half of the skin snips taken from the village residents. The prevalence of onchocerciasis as diagnosed from skin snips increased with age, and was greater for males than females. The number of microfilariae per skin snip also increased wth age. The presence of subcutaneous nodules, inguinal lymphadenopathy, microfilariae in the urine, ocular lesions and prolonged itching all were related to both age and the presence of microfilariae in skin biopsy specimen, as well as to intensity of infection. Microfilaruria was not restricted to individuals with severe onchocerciasis.