Between November, 1988 and April, 1991, parasitological and symptomatological methods of diagnosis were used to survey the prevalence of mansonellosis among the Ibo population in Abia and Imo States of Nigeria. 1,197 or 28.6% of the 4,183 persons examined were positive for microfilariae of Mansonella perstans. The prevalence of mansonellosis was significantly higher (P < 0.05) among rural dwellers (34.6%) than among urban dwellers (22.5%), in males (30.8%) than in females (26.3%), in farmers (59.8%) and palm wine tappers (46.1%) than in civil servants (7.6%), and in persons 21 years of age and above (36.2%) than in those in the first two decades of life (9.4%). Clinical signs observed in most infected persons include body itching, joint and back pains, occasional giddiness and elephantoid scrotum. Body itching was the most commonly observed clinical sign (14.7%), followed by joint pains (12.41%) with elephantoid scrotum (3.5%) as the least. The public health implication of the findings is discussed.