Considering all the available data, the current study was conducted to investigate the effects of metformin and/or L-ascorbic acid on cytotoxicity, oxidative stress; melanin, cAMP and L-3,4-dihydroxyphenylalanine (L-DOPA) and tyrosinase levels and tyrosinase gene expression in melanoma cell line (MNT-1). The gene discussed is TYR; the disease is melanoma.