Twenty-four patients have been treated by regional isolated perfusion with decarbazine for melanoma of an extremity, with a follow-up period of seven to 72 months. None of these patients had any signs or symptoms of toxicity from the drug. The serum glutamic-oxalacetic transaminase level was elevated by the first postoperative day and returned to normal within the next six days. Fourteen of these 24 patients are free of disease for a follow-up period of 23 to 70 months. Three of the seven patients treated for local or intransit metastases are free of disease for five, 60 and 61 months; a fourth patient had subcutaneous metastases of the trunk develop while remaining disease-free in the perfused extremity for 72 months, and a fifth patient perfused for numerous intransit metastases of a leg had resolution of many of the nodules and remains without new lesions for nine months. Decarbazine is recommended as a safe and valuable drug for the perfusion of extremities with melanoma.