Thirty-three patients with disseminated malignant melanoma were entered in a phase II study of the new nitrosourea S 10036 using a 100-mg/m2 weekly induction schedule for 3-4 consecutive weeks. Patients who responded to this treatment were followed with a maintenance therapy every 3 weeks. Toxic effects were mainly hematological and consisted of delayed thrombocytopenia and leukopenia. Among 30 patients who could be evaluated, eight partial responses were observed (response rate, 26.67%); among seven patients with cerebral metastasis, two partial responses were observed. This multicentric study is currently being continued to confirm this interim report.