On the basis of clinico-morphological analysis of 104 patients with malignant skin lymphomas (MSL) they are subdivided into two groups: epidermotropic (mycosis fungoides, prolymphocytic and lymphoblastic MSL with sinuous nuclei, histiocytic MSL) and non-epidermotropic (prolymphocytic MSL with roundish nuclei, microlymphoblastic and immunoblastic MSL). The former group differs from the latter by the involvement of the epidermis, with hyperplasia of keratinocytes and the disturbance of their differentiation, penetration of tumour cell into the epidermis and by the composition, type and localization of the proliferate. Epidermotropic MSL were much more frequent, affected younger persons, had a longer duration, more widespread skin involvement with polymorphic eruptions. Non-epidermotropic MSL were characterised by the appearance of single tumours of the skin and early generalization.