Diarrhoea disease is one of the major causes of morbidity and mortality in infants and young children, especially in the developing countries. Rotavirus is the most common cause of acute diarrhoea in children under 2 years of age worldwide and has been reported as a cause of endemic viral diarrhoea in children in Nigeria. This study aimed at determining the prevalence and symptomatology of rotavirus induced diarrhoea and assessing the understanding of caregivers on the causation of diarrhoea diseases in children less than 5 years of age in Ilorin, Nigeria. Two hundred and ninety-nine (299) patients below 5 years who presented with diarrhoea and 240 age-matched subjects without diarrhoea for the preceding 2 weeks (as control) were recruited during this study period, which spanned from December 2003 to November 2004. On recruitment, the basic bio-data were collected. Fresh stool samples from subjects were processed for viral studies by ELISA and electropherotyping. Sixty-three (21.1%) and 167 (55.9%) of the 299 patients were positive for rotavirus by ELISA and electropherotyping respectively. Rotavirus was significantly higher among inpatients. Breastfeeding was not protective against rotavirus. The more common clinical features associated with diarrhoea in the study were vomiting (34%), fever (31.7%) and dehydration (13.2%). Majority of caregivers (54.8%) did not know possible cause of diarrhoea disease, while another 28.2% attributed it to teething; only 4.8% related it to hygiene. It is concluded that: (1) Rotavirus is an important cause of diarrhoea in children in Ilorin and it is frequently severe, requiring more admissions. (2) Electropherotyping is more sensitive in rotavirus detection; (3) Older age group rather than breastfeeding is protective against rotavirus induced diarrhoea and (4) the understanding of caregivers on the possible causes of diarrhoea in this environment is inadequate. It is therefore recommended that electropherotyping should be used routinely in the detection of rotavirus in stool samples. There is need to reach out to the public with appropriate health education tools in order to reduce the prevalence of diarrhoea diseases in this environment. Finally, aggressive rehydration should be carried out for all diarrhoea patients requiring admission on account of dehydration.