Congenital diffuse Melanosis is one of the rarest clinical manifestations of hereditary universal Melanosis and only few cases have been reported all over the world. The presented case is a 54-year-old man who presented to us complaining of erythematous annular lesions on his face and neck since 8 months ago. Diffuse pigmentation of his skin took our attention. According to the patient, diffuse hyperpigmentation was present at birth and there was no obvious changes up to now. His mother and sister had similar hyperpigmentation. He had 2 sons with a similar hyperpigmentation, but his daughter had normal skin pigmentation. All laboratory investigation for the causes of hyperpigmentation were reported normal and investigation for causes of secondary hyperpigmentation did not reveal any abnormality. In histopathological assay, the erythematous lesion was reported to be discoid lupus erythematous and the diagnosis of hyperpigmented lesion reported as congenital diffuse Melanosis.