Melanoma cell oncolysate, prepared with Newcastle disease virus, was administered as an immunostimulant to 13 patients with metastatic melanoma. The oncolysate was well tolerated. Six treated patients evidenced a decrease in the size of skin nodules or diseased lymph nodes. Visceral lesions were not favorably influenced to any marked degree. One case of fulminating disease showed a change to slow progression and survived a year longer than was otherwise expected. Another patient, whose melanoma could not be controlled by surgery or chemotherapy, has been in complete remission for 2 years. It appears that viral oncolysate might be particularly helpful to patients with early disease.