In an analysis of sporadic cases of gastroenteritis in children, rotaviruses were detected in 61 out of 363 specimens examined. Studies of rotavirus isolates by polyacrylamide gel electrophoresis (EP) of RNA revealed 9 different EP types. In one region, during the entire epidemic season one "long" EP type was prevalent. In one patient, a mixture of a "short" and "long" EP types was detected. In another region, "atypical" rotaviruses were found not belonging to the antigenic group A of rotaviruses.