Primary anorectal malignant melanomas represent have an incidence from less than 0.2 to 1%. The present article addresses a case of a 63 years old male with a five centimetres diameter bulk in the right quadrant , irregular surface, highly vascularized indurated areas alternating with reluctant areas, eroded and with scanty bleeding. Complete excision of the lesion was performed, leading to a diagnosis for anal malignant melanoma through the discovery of tumor cells positive for Melan-A and S-100 and negative for citokeratine AE1/AE3.