Norovirus and rotavirus are important causes of acute nonbacterial gastroenteritis in communities worldwide. Genotypes of norovirus and rotavirus in stool samples, which were collected from patients, was determined by RT-PCR and ELISA. A total 4,484 stool samples (461 outbreak cases) collected during January 2010-April 2013 were analyzed. Four hundred thirty eight of samples were positive for norovirus. Twelve samples were positive for Rotavirus. Norovirus genotypes identified were nine kinds of G I genotype (G I -1, G I -2, G I -3, G I -4, G I -6, G I -7, G I -9, G I -12, G I -13) and nine kinds of G II genotype(G II -2, G II -4, G II -5, G II -6, G II -7, G II -11, G II -12, G II -15, G II -16). Rotavirus genotypes were G2P. The results might be useful information for evaluating the epidemiological status of viral diarrhea in Seoul, and providing a strategy to prevent human norovirus, rotavirus and other threats to public health in Korea.