A third-generation platinum analogue, zeniplatin, was administered at a dose of 145 mg/m2 intravenously over 60-90 minutes every 21 days as the initial chemotherapy to 21 patients with metastatic melanoma. Prehydration and mannitol diuresis was introduced after the first 7 patients. There were 17 males and 4 females. The median age was 52 (range: 29-81). ECOG performance status was 0 in 10 patients, 1 in 8 patients and 2 in 3 patients. Major disease sites were lymph nodes, skin, lung, liver, and bone. Patients received a median of 2 cycles (range: 1-7). Two patients achieved partial responses. One with nodal disease progressed after 166 days and the other with buccal mucosal disease after 142 days. A third patient showed partial regression of nodal disease but developed cerebral metastases. Gastrointestinal toxicity included WHO grade 3 vomiting in 8 patients and nausea in 2. Antiemetics were used, but ondansetron was not available. WHO grade 3 hematologic toxicities included neutropenia in 8 patients and anemia and thrombocytopenia in 1 patient. Thrombocytosis was seen in 35% of courses. Dosage reduction was required in 15% of courses and escalation in 5% of courses. Three patients developed phlebitis related to the infusion. One patient developed a reversible rise in serum creatinine, but, unlike other studies, no severe nephrotoxicity was reported. Zeniplatin demonstrated only modest activity in melanoma with significant gastrointestinal and hematologic toxicity.