The Scandinavian Mycosis Fungoides Study Group includes dermatologic clinics in Denmark, Norway, and Sweden. The results of the first three years of activity are presented herein. In plaque stage, topical nitrogen mustard was highly effective. Preceding intravenous tolerance induction seems to be of no value. PUVA induced equally high remission rates. Both modalities were also highly effective in cutaneous tumor stage. In advanced tumor stage and in case of extracutaneous involvement systemic chemotherapy was given. Topical treatment alone was more effective on the cutaneous lesions including tumors than systemic chemotherapy alone. Therefore a combination of topical and systemic treatment is recommended in advanced stages of mycosis fungoides.