Melanogenesis is a physiological process resulting in the synthesis of melanin pigment. We investigated the inhibitory effect of crude polysaccharide of water extract of Artemisia iwayomgi Kitamura (AI) on melanin biosystheies in B16/F10 melanoma cells. Crude polysaccharide of water extract of Artemisia iwayomgi Kitamura significantly inhibited tyrosinase activity and melanin contents with or without $alpha$-MSH in vivo. Melanin contents and tyrosinase activity were decreased in a dose-dependent manner,These results show that crude polysaccharide of water extract of Artemisia iwayomgi Kitamura could be developed as skin whitening components of cosmetics.