Electropherotypes of human rotavirus from stool samples of hospitalized and ambulatory infants with acute diarrhea were analysed. Thirty-two different electropherotypes were observed in 142 cases in which the viral genome RNA was characterized. The seasonal distribution of the electropherotypes, from 1979 to 1981, showed that the same electropherotypes were detected throughout the period of study while others were found only occasionally. Electropherotypes were also analyzed depending on whether the patient from whom they had been obtained required hospitalization or was treated at home. The analysis shows that the electropherotypes were equally distributed in both groups of patients.