An epidemiological survey of guinea worm infection was carried out in 17 rural village communities north of Ibadan in western Nigeria from 1971 to 1975. The incidence was 13.5% in a population of 8,200. The sexes were equally affected although there were significantly more cases amongst boys than girls. A majority of the worms emerged from the lower limbs and the incidence of complications and disability was higher in those with lesions around the ankles and feet. The average duration of incapacity from effective work among this predominantly rural population was 100 days. A case is made for a concerted effort to eradicate this easily prevented disease by the provision of wholesome potable water to all persons.