Purpose: This study was performed to elucidate the inhibitory effect of Yukmijihwangtang-gagambang (YMG) on melanin synthesis in B16F10 mouse melanoma cell. Methods: To demonstrate the inhibitory effects of YMG on melanin synthesis, we measured the amount of released and produced melanin in B16F10 melanoma cell. Also, we evaluated tyrosinase-activity in vitro as well as in B16F10 melanoma cell. And to investigate the action mechanism we assessed the gene expressions of tyrosinase, TRP-1, TRP-2, MMP-2, PKA, PKC${eta}$, ERK-1 ERK-2, AKT-1 and MITF in B16F10 melanoma cells. Results: 1. YMG decreased the release and production of melanin in B16F10 melanoma cells. 2. YMG decreased tyrosinase activity in vitro and in B16F10 melanoma cells. 3. YMG decreased the expression of tyrosinase, TRP-1, TRP-2, PKA, PKC${eta}$ and MMP-2 in B16F10 melanoma cells. 4. YMG increased the expression of ERK-1, ERK-2, and AKT-1 in B16F10 melanoma cells. 5. YMG decreased the expression of MITF in B16F10 melanoma cells. Conclusion: From these results, we suggest that YMG inhibit melanin synthesis via tyrosinase inhibition and regulation of the gene expression in B16F10 melanoma cells.