In this study, we investigated the molecular epidemiology of group A rotaviruses in cases of acute gastroenteritis in Goroka, Papua New Guinea. From April 2008 through November 2010, 813 diarrheal stool samples were collected from children < 5 years of age hospitalized with acute gastroenteritis. Rotavirus antigen was detected in 31.2% of samples using a commercial enzyme-linked immunosorbent assay. Genotyping revealed the presence of the globally circulating strains G1P[8] (50.0%), G3P[8] (23.0%), and G2P[4] (8.2%). The globally emerging strains G9 and G12 were detected in 1.2% and 6.1% of samples, respectively. Mixed infections were detected in a high proportion of samples (11.9%), with 9.0% and 3.7% of samples displaying multiple G and P genotypes, respectively.