To identify the natural and novel cosmeceutical ingredients which have whitening function, we examined the effects of tyrosinase activity and melanin production on halophyte Limonium tetragonum (Thunb.) A. A. Bullock extracts. As a result, the extracts showed whitening effect with no cytotoxicity. Melanin contents of B16F10 melanoma cells were decreased in a dose-dependent manner at 50, 100, 200 μg/mL treatment of the extracts. In tyrosinase activity inhibition test, L. tetragonum (Thunb.) A. A. Bullock extracts showed decreased tyrosinase activity as the concentration of α-MSH was increased. Furthermore, it was observed that the tyrosinase and MITF expression was significantly downregulated by adding L. tetragonum (Thunb.) A. A. Bullock extracts in α-MSH, a melanogenesis inducing material, treated B16F10 melanoma cells. These results indicate that L. tetragonum (Thunb.) A. A. Bullock extract might be an effective whitening agent by inhibit melanin formation.