Irradiation of the melanin-containing fungi Cladosporium transchelii, its pigmented mutants, Stemphyllium ilicis, Oidiodendron cerealis, and isolated melanin pigment with UV or visible light leads to an increase in the concentration of paramagnetic centers (PC) in melanin pigments, recorded by the EPR technique. Differences were established in the reaction of melanin of UV-sensitive and UV-resistant cultures to illumination. Paramagnetic centers are generated by a single-quantum mechanism (light with lambda less than 900 nm was active). A mechanism is proposed for processes occurring during illumination of dark-pigmented subjects, which includes photoinduced electron transport in melanin and dark recombination of the PC formed in the process.