The electrophoretic typing of 1,370 rotavirus strains revealed the presence of group C rotaviruses in 1.3% of cases. In the Arkhangelsk region group C rotaviruses were detected in 34.4% of cases. The detected group C rotaviruses were shown to be no different in their morphology from typical ones; they were characterized by the variability of their genome and the absence of hybridization with RNA of group A rotaviruses. Group C rotaviruses were detected in children aged 3-6 years; in this age group they caused both sporadic morbidity and an outbreak of infection. The clinical manifestations of gastroenteritis caused by group C rotaviruses were no different from typical rotavirus gastroenteritis.