Background: Melanocytes are involved into the synthesis and metabolism of steroid hormones in the skin. Cutaneous melanoma in 75% of cases occurs in congenital or acquired pigmented nevi. There are no studies comparing local hormonogenesis in nevi and melanomas. The purpose of the study was a comparative analysis of hormone levels in tissues of dysplastic nevi and cutaneous melanoma (pТ_1-2N₀M₀). Methods: Levels of prolactin (PRL), progesterone (P4), total and free testosterone (T and fT), estrone (E1) and estriol (E3) and sex steroid-binding globulin (SSBG) were studied by ELISA in 17 samples of рТ_1-2N₀M₀ melanoma and in 23 samples of dysplastic nevi. Intact tissues (n = 15) obtained from non-cancer patients during surgical treatment was used as the control. Results: Levels of T in nevi, compared to intact tissues, were 1.4 times higher, fT – 8.7 times higher, while SSBG content was 1.9 times lower; E3 was 1.6 times higher, PRL – 1.4 times lower, and levels of E1 in nevi were similar to the values in intact tissues. рТ_1-2N₀M₀ melanomas, compared to intact tissues, demonstrated local androgen imbalance: T levels were decreased by 1.8 times, while fT exceeded the norm by 1.8 times, and SSBG – by 6 times. E1 content increased by 1.6 times, E3 decreased by 2.8 times. The E1/E3 ratio in nevi was reduced by 1.6 times, while in melanoma it was increased by 4.4 times. The T/E1 ratio in nevi was increased by 1.4 times, and in melanoma it was decreased by 2.8 times. Levels of PRL and P4 in melanomas, nevi and in intact tissues did not differ significantly. Conclusions: Melanoma was characterized by hyperestrogenia due to increased levels of E1 and low E3 concentrations which caused malignant transformation of melanocytes. Most likely, in melanoma spent SVT estrone synthesis, as evidenced by increase in the E1 / E3 and decrease T / E1.Apparently, fT in melanoma is used for estrogen synthesis, as indicated by the E1/E3 increase and decrease in the T/E1 ratio. Increased E1 synthesis can contribute to the realization of estrogen genotoxic effects. These mechanisms are absent in tissues of nevi. Hyperandrogenism in nevi probably prevents malignant transformation due to low aromatase activity.