Two human G12 rotaviruses, CAU 195 and CAU 214, were isolated from South Korea using cell culture and characterized on the basis of sequence divergence in the VP7, VP4, and NSP4 genes. Phylogenetic analysis of the VP7 gene sequences indicated that these strains clustered into lineage III and were most closely related to G12 rotaviruses isolated in the United States. The VP4 and NSP4 gene sequences showed that two strains belonged to the P[6]-Ia lineage and genotype [B]. This finding provides information that can be used to evaluate G12 strains and aid in the development of effective vaccines in the future.