The aetiology of intussusception is ill-defined, with viruses being incriminated as one of many possible aetiological agents. A two-part study was performed by us to investigate the aetiological role of rotavirus in intussusception. Retrospective epidemiological data revealed a negative correlation between the incidence of rotaviral gastroenteritis and the incidence of intussusception. A prospective investigation employing electronmicroscopy, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence studies of faeces and fluorescent antibody studies of sera demonstrated evidence of rotavirus infection in only 2 of 24 children with intussusception. No evidence was forthcoming in this study of an aetiological role of rotavirus in intussusception.