We previously reported that the activity of antibody dependent cell-mediated cytotoxicity (ADCC) of lymphocytes from the patients with urinary bladder carcinoma was lower than that of normal subjects. We performed the specific ADCC assay using SRBC as the target cells, coated with tumor extract from the urinary bladder carcinoma. At the same time, the antiserum was collected from the immunized rabbit by the same tumor extract. The addition of the antiserum from the immunized rabbit gave the highest value for the patient sub-group that produced a precipitin band (Ouchterlony gel diffusion assay). Therefore it is suggested that the reaction of lymphocytes to tumor associated antigens is maintained to a considerable extent, although ADCC activity of the patient group was decreased. However, the antibody producing phenomenon toward the tumor associated antigen might be restrained.