In order to search for anti -melanin formation agents from Korean medicinal herbs, we selected 21 Korean medicinal herbs, based on a review of Korean traditional medicine books and the recommendations of Korean traditional medical doctors. We tested for inhibition effect of melanin pigmentation of Clone M-3 mouse melanocyte cell lines when we treated the extracts of 21 medicinal herbs in the mouse melanocyte cell lines, respectively. Among 21 medicinal herb extracts, 5 extracts showed a inhibition effect of melanin formation. The sample Phaseolus radiatus L, Cordyceps militaris, Pinellia ternata, Phellinus linteus and Citrus junos Tanaka showed a significantly little formation of melanin pigments compared with control groups. Especially extract of Citrus junos Tanaka was more potent than the others. These results suggest that extract of Korean Citrus junos may represents an excellent candidate for inhibition of melanin pigmentation at in vitro level.