The aim of this study was to investigate the effect of Fructus Forsythiae on the melanogenesis. To determine whether Fructus Forsythiae methanol extract suppress melanin synthesis in cellular level, HM3KO human melanoma cells were cultured in the presence of various concentrations of Fructus Forsythiae methanol extract and the effects on cell proliferation, tyrosinase activity and melanin contents were examined. Treatment with Fructus Forsythiae methanol extract inhibited tyrosinase activity, regulate melanin biosynthesis as the key enzyme in melanogenesis, in a dose-dependent manner. And also suppressed melanin contents as a dose dependent manner without cytotoxicity morphological change. It was observed that the color of cell pellets was totally different from the control. These results suggest that the inhibitory effect of Fructus Forsythiae methanol extract on melanogenesis is due to the suppression of tyrosinase in HM3KO cells and Fructus Forsythiae is a candidate for an efficient whitening agent.