A total of 65 patients with advanced cutaneous malignant melanoma (MM) have now been treated with interferon alpha-2b (Intron A) at a dose of 10 million IU/m2 administered subcutaneously thrice weekly. Fifty-one patients were evaluable for response, and 4 of these (7.8%) achieved complete remission; 2 of these 4 remain so at 37+ and 54+ months. Six additional patients achieved a partial remission. All responders had subcutaneous, lymph node and/or pulmonary metastases only. In all responders, therapy was continued for a total of 12 months. The vast majority of patients experienced side effects, largely flu-like symptoms, mild leukopenia and mild hepatocellular dysfunction. No evidence of cumulative toxicity was observed. Our experience indicates that interferon alpha-2b is active in patients with advanced cutaneous MM.