Melanocytes ⁱ/mɛˈlænɵsaɪt/ are melanin-producing cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear,meninges,bones, and heart. Melanin is a pigment that is responsible primarily for the color of skin.

Through a process called melanogenesis, these cells produce melanin, which is a pigment found in the skin, eyes, and hair. This melanogenesis leads to a long-lasting pigmentation, which is in contrast to the pigmentation that originates from oxidation of already-existing melanin.

There are both basal and activated levels of melanogenesis; in general, lighter-skinned people have low basal levels of melanogenesis. Exposure to UV-B radiation causes an increased melanogenesis. The purpose of the melanogenesis is to protect the Sucutis, the Hypodermisas, the layer under the skin, from the UVB light, that can give it damage it (DNA photodamage). The color of the melanin is dark and it absorbs all the UVB light and it blocks it from passing the skin layer.