To improve detection of norovirus (NoVGI, NoVGII) and sapovirus (SaV), a simultaneous quantitative RT-PCR method was established. This triplex real-time PCR method was evaluated using a combination of optimized specific primers and probes. The performance of the developed PCR assay was equivalent to that of monoplex real-time PCR across a broad dynamic range of 102–107 copies/assay using plasmid DNA standards. The limit of detection was 102 copies/assay. The quantitative value was comparable with that of monoplex real-time PCR of stool samples. Our triplex real-time PCR is useful for detection of NoV and SaV infections.