A survey on mansonellosis was carried out in Bauchi State of Nigeria between January 1990 and March 1992. Of the 5,640 inhabitants examined, 24 (0.4%) were positive for Mansonella streptocerca microfilariae. Microfilaria rate and mf density increased gradually with host age. While infection and sex are independent, mansonellosis was significantly lower in subjects within the first three decades of life than in those above 31 years (P < 0.05). Clinical signs observed include pruritus, rash, inguinal adenopathy and occasional dizziness. Skin biopsies taken from the shoulder gave the highest frequency of positive skin snip.