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[4]. 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.