From November 2008 to January 2009, a sharp increase of diarrhea in children in Guangdong province appeared, we randomly collected 53 stool specimens from out-patient children with dirrhea in 3 major hospitals (Guangzhou City Children's Hospital, Shenzhen Baoan District Maternal and Child Health Hospital, First Affiliated Hospital of Shantou University). Rotavirus and calicivirus were screened by ELISA and RT-PCR. We found 29 cases of rotavirus infection with diverse serotypes. Only four cases were identified as calicivirus infection. The result indicated that rotavirus was a major pathogen of this high incidence of diarrhea from November 2008 to January 2009 in Guangdong Province.