Properties of a virus isolated from a patient with rotavirus gastroenteritis (the diagnosis verified by direct electron microscopy) were studied. The virus was identified as a rotavirus in tissue culture neutralization and complement fixation tests. It was shown to replicate through a significant number of passages in continuous cell cultures (Vero, RH) as well as in primary cell cultures of human and animal origin (human embryo kidney, green monkey kidney); some features associated with rotavirus propagation are described.