Petalonia binghamiae extracts (PBE) suppressed melanin synthesis in a dose-dependent manner in $alpha$-melanocyte stimulating hormone ($alpha$-MSH)-treated B16/F10 murine melanoma cells. Specifically, the cell tyrosinase activity and melanin content were inhibited by 72% and 48%, respectively, in response to treatment with 100 ${mu}g$/mL of PBE. The results of western blot analysis suggest that PBE induced the inhibition of tyrosinase and TRP-1 protein expression through suppression of $alpha$-MSH induced p38 and ERK activation.