Melanins are pigments widely distributed in living organisms. In humans melanin is synthetised in the retina, choroid and epidermis. Melanins fulfil a protective function and are responsible for the color of eyes, skin and hair. Melanogenesis is a process undergoing in specialized organelles of melanocytes--melanosomes. After synthesis, melanin is transported to target cells--keratinocytes. The key enzyme of the melanin synthesis pathway is tyrosinase. Many agents used in the treatment of hyperpigmentation act as tyrosinase inhibitors. Depigmenting agents and those increasing melanin synthesis are used in medicine and cosmetology. Also natural plant melanins extracted from e.g. Nigella sativa, have interesting effects on mammalian cells. In the current review paper we present methods used for identification of melanin and melanocytes in diagnostics of disorders affecting melanogenesis process.