Two cases of melanic hyper-pigmentation in Lepidion lepidion are reported from two localities in Spanish Atlantic waters. A bibliographic search revealed the occurrence of this chromatic anomaly in two other Lepidion specimens, the first of them reported in the late 19th century. Macroscopically, the colour abnormality was characterized by the presence of numerous cutaneous irregular dark patches over the head, body and fins. Microscopically, melanosis corresponds to hyperplasia of dermal melanophores. Although the cause of the hyperplasic proliferation of pigmented cells could not be determined, possible aetiologic agents were proposed. This is the first histopathological study of a melanic specimen of the genus Lepidion.