Over the past 7 years, 151 patients with malignant melanoma have been treated with BCG immunotherapy alone or as an adjunct to surgical therapy. Direct injection of metastatic melanoma lesions limited to skin resulted in 90% regression of injected lesions and 17% regression of uninjected lesions in immunocompetent patients. Approximately 25% of these patients remained free of disease for 1 to 6 years. Direct injections of BCG into nodules of patients with subcutaneous or visceral metastases resulted in a lower incidence of local control and no long term survivors. Attempts to improve the results of immunotherapy in these patients by palliative surgical resection of large metastatic lesions to lower tumor burden followed by BCG immunotherapy significantly improved the results although many patients still developed recurrent disease. Early results of a clinical trial combining BCG immunotherapy with regional lymphadenectomy in patients with melanoma metastatic to lymph nodes have been encouraging and promising. Further controlled clinical trials are necessary to elucidate the role of BCG in immunotherapy. However, since BCG is but one of a number of potential immunologic adjuvants, even more effective immunotherapy will be possible as further knowledge of the interactions of cellular and humoral immunity is acquired.