Objective To characterize the etiological pathogens of epidemic diarrhea in hamster infants. Methods To collect feces from the hamster infants and detect the possible viruses, bacteria or parasites. RNA electrophoresis for rotavirus identification was performed using a group A rotavirus diagnostic kit. Results No definite bacteria or parasites were detected. Group A rotavirus was not detected. RNA electrophoresis showed 11 bands in patterns resemble to that of group B rotavirus. Conclusion The epidemic diarrhea in hamster infants is caused by group B rotavirus.