A 35-year-old man with acute monocytic leukemia (AMoL) cutis was treated with total skin electron beam irradiation (TSEBI), because the widespread skin infiltration of AMoL appeared after induction chemotherapy. A skin nodule was authenticated as leukemic cell by biopsy. The patient was irradiated 4 times a week with 200 cGy per fraction to a total dose of 1200 cGy, using 6 MeV electrons from 8 directions. The therapy was accomplished separately on the upper and lower halves of the body. Focus-skin distance was 310 cm. An acrylic plate applicator 1 cm in thickness was used. The dimensions were 90 x 90 cm inside length and 90 cm in height. After completion of radiotherapy, the nodular lesions of the skin nearly disappeared. Although the patient survived only 3.5 months after beginning of radiotherapy due to systemic relapse, recurrence of the skin nodule was not seen. In this case TSEBI was therefore a useful treatment for skin infiltration of AMoL.