Stool samples from 392 infants and young children attending various clinics in Zaria, Northern Nigeria from June 1986 to May 1987 were analysed by ELISA for the presence of rotaviruses. There was a prevalence of 27 per cent in these children with the virus being most prevalent in the first 6 months of life. This decreased with age until it was less than 10 per cent in children 3-5 years old. Although rotavirus was found to be present throughout the year; there was a much higher prevalence during the dry season (October to April) as compared to the wet season. Infection with the virus correlated inversely with relative humidity, vapour pressure and minimum temperature showing considerable influence of these climatic factors on rotavirus infection in children in Zaria.