Background: Mycosis fungoides (T-cell non-Hodgkin’s lymphoma) is a quite rare neoplasia, which follows an indolent course, characterized by presenting epidermotropism in spite that there is a possibility of compromise of structures like lymph nodes and visceral organs. Its incidence increases starting from the fourth decade of life with posterior drop after more or less the age of 80, having preference for men. Objective: To analyze the role of radiotherapy in the therapeutic approach of patients with diagnosis of mycosis fungoides. Conclusions: Radiotherapy is indicated for patients suffering from mycosis fungoides in all stages especially when the disease has affected more than 50% of the body surface. Starting from stage IB, total skin irradiation is employed with a dose of 30 to 36 Gy with boost at medical criterion.