Twenty-five patients with visceral predominant metastatic melanoma will be treated with whole body hyperthermia to 42 C for 2 hours using the A-V shunt heat exchange method of heat induction with general endotracheal anesthesia. Patients with brain metastases will be excluded in this study. Continuous arterial blood pressure, venous blood pressure, Swan-Ganz pulmonary artery wedge pressure, and EKG will be monitored throughout the procedure. Serial esophageal, pulmonary artery, jugular bulb, rectal and bladder; facial, chestwall, abdominal wall and shin skin temperatures will be monitored and recorded. If skin or subcutaneous metastases are present, two thermistor probes will be placed in at least two tumors. One thermistor will be inserted at the tumor periphery and one at approximately the tumor center. Suitable intraabdominal tumors will have thermistor probes placed in the arterial and venous tumor vessels using an angiographic technique. Serum lactate gradients, PO2 concentration and pH will be measured at 30 minute intervals from the same catheter. Three weeks after the first exposure to heat the patients will be examined for toxicity and objective tumor change. Following complete evaluation with studies appropriate to pretreatment tumor documentation, they will be again heated to 42C. At 42C the first ten patients, in groups of two, will have administered escalating doses of chlorozotocin IV beginning at 100 mg/M2. The last 15 patients will be examined at maximum dose level (approximately 150-175 mg/M2). The patients will be maintained at 42C for 2 hours after administration of the intravenous chlorozotocin. Following medical evaluation including cardiac, lung and renal function as well as appropriate studies to document tumor response, the 2 hour 42C heat-chemotherapy protocol will be repeated at 6-8 week intervals depending on hematologic toxicity and tumor response. Following the intravenous administration of chlorozotocin, serum and urine levels for chlorozotocin as well as tumor gradient levels when obtainable, will be collected at 5 minute intervals for 3 hours, then at 24, 36, 48 hours and will be analyzed. Three patients not candidates for hyperthermia will receive chlorozotocin as a single agent and the same serum and urine assays will be performed.