Two-hundred-and-seventeen children admitted with diarrhoea and 204 unmatched controls hospitalized during the 2-year period from November 1990 to October 1992 were included in this prospective study. Their stool samples were subjected to microscopy, cultures, ELISA for rotavirus and electron microscopy. Human rotavirus (HRV) was detected in 68 (31 per cent) of the stool samples in the study group and 12 (6 per cent) in the control group. There was an increased incidence in the cooler months of the year; typically, most of the affected infants and children presented with vomiting and respiratory symptoms, and had mild to moderate dehydration. Biochemical profile showed normal or hyponatraemia and normokalaemia. A more detailed community-based study of diarrhoeal diseases in Oman is to follow this pilot study.