Summary The impact of a school health club on adult perception of onchocerciasis and compliance with ivermectin was evaluated in an onchocerciasis-endemic community in southeastern Nigeria. Venous blood was collected from each of 26, 32 and 124 randomly selected subjects during ivermectin distribution programmes in 1995 1996 and 1997 respectively. Ivermectin concentrations were measured in the samples. Data was also collected from 334 and 319 randomly selected household heads or their representatives (aged 24 to 65 years) before and after health talks by schoolchildren, using interviewer-administered questionnaires. There was an increasing number of subjects who participated in control programmes (116 in 1995, 437 in 1996 and 2055 in 1997). Compliance with ivermectin treatment was low (53.9%) in 1995 but increased dramatically (90.1%) in 1997. A significant proportion (χ2= 108.7, df = 1, P < 0.0001) of respondents knew about onchocerciasis after health education, predominantly from health workers (64.5%) before the tests and children (92.3%) after. Knowledge and beliefs about causative agents (χ2= 266.4, df = 5, P < 0.0001), diagnostic method (χ2= 207.4, df = 3, P < 0.0001), prevention (χ2= 67.0, df = 4, P < 0.0001) of onchocerciasis and the effectiveness of ivermectin (χ2= 40.4, df = 1, P < 0.0001) also differed significantly between the periods before and after tests. The school health club increased adult knowledge about onchocerciasis and its treatment. Schoolchildren could therefore supplement the information, education and communication (IEC) aspect of health care delivery in a community through such health clubs.