Ten fatty acid alkyl esters isolated from Oxalis triangularis, were evaluated for the effects on melanogenesis using mouse B16 melanoma cells. Treatment of methyl linoleate, methyl linolenate, ethyl linoleate and ethyl linolenate significantly blocked forskolin-induced melanogenesis and inhibited tyrosinase activity. In addition, we found that they inhibited cAMP production, suggesting that their anti-melanogenic effect is mediated by the inhibition of cAMP production. We concluded that methyl/ethyl linoleate and linolenate isolated from Oxalis triangularis have pigment inhibition activity. These compounds may be useful as the cosmetic agent to stimulate skin whitening.