Since Morton demonstrated in 1968 that malignant melanoma is antigenic, many immunologists have taken an interest in this disease. A basis for specific active immunotherapy has been worked out at Duke University Medical Center, Durham, N.C. (USA). A female chimpanzee was hyperimmunized with melanoma cells grown in tissue culture. After appropriate absorptions the xeno-antiserum was tested by indirect immunofluorescence. Apart from unspecific activities in the serum detectable against normal human fetal and adult fibroblasts as well as other non-melanotic human tumors, following further absorptions with these cells a melanoma-specific antigen could be demonstrated on the surfaces of melanoma cells. The melanoma-specific tumor-associated antigens were further evaluated by direct and indirect immunoautoradiography. These studies suggest that there are indeed cross-reacting specific tumor-associated antigens on the cell surface of melanoma cells. At DUMC melanoma patients have therefore been hyperimmunized with melanoma cells + BCG. Clinical experience is discussed.