Following a previous preliminary report, this study was initiated to demonstate further evidence of tumor-associated antigens in Hodgkin’s disease and to determine if these antigens are found in other pathologic states. Tumor-associated antigens are now demonstrated by three techniques in 18 Hodgkin’s invoved spleens and are not found to be present in equal concentration in normal spleens. Using immunofluorescence techniques and absorbed tumor antisera, fluorescence is demonstrated in tumors but not in the normal region of the same tumor-bearing spleen or in normal spleens. Gel diffusion with absorbed tumor antisera revealed a common precipitin band in Hodgkin’s disease not present in normal spleens or spleens from other diseases. Studies with immunoelectrophoresis have demonstrated two antigens present in the tumors in the spleen. Eighteen out of 19 Hodgkin’s tumors from the spleen have such antigens identifiable by immunoelectrophoresis with concomitant negative normal splenic controls in each case. Five out of 18 spleens from other disease states shared one of the antigens. These data confirm the presence of common tumor-associated antigens in Hodgkin’s disease, and it is postulated that at least one antigen may be a host cell reactant substance.