Dematiaceous fungi are dark brown, olivaceous or black pigmented groups of fungi. As only and shared characteristic, they belong to the class of Deuteromycetes, order Moniliales, genus Hyphomycetes, and they produce melanin or dihydroxinaphtalene-melanin. Their identification is mainly based on their morphological structure. In this review article, some microscopic properties and differentiation criteria have been discussed for the morphological identification of these fungi.