A total of 2312 children admitted to the Nizhni Novgorod infectious disease hospitals for diagnosed acute gastroenteritis were examined using the RT-PCR. The detection rate of human caliciviruses was found to be 6.5% (range 1.2 to 11.2%). The population of calicivuruses presented with noroviruses genogroups I (16%) and II (81%), and sapoviruses (3%). Noroviruses genogroup II included genotypes GII.2 and GII.4 with a preponderance of the variant CII.4-2006b. The detected sapoviruses were clustered with sapoviruses GI.1, GI.2, and GII.1 by phylogenetic analysis.