Plasma carcinoembryonic antigen (CEA) levels were performed preoperatively by radioimmunoassay in 124 patients with histologically proved bladder carcinoma. The level of CEA was used to determine its porgnostic value in patients with bladder cancer. The correlation of CEA levels with the stage of the disease, histology and resectability was also studied. Values above 2.5 ng/ml were taken as abnormal. Active disease was associated with high CEA levels. All patients with CEA levels greater than 10 ng/ml died in less than 1 1/2 yr, while all patients who survived 1 1/2-3 yr had preoperative CEA levels less than 10 ng/ml. There was a prognostic significance for patients with transitional cell or squamous cell carcinoma. All patients with squamous cell carcinoma had CEA levels .ltoreq. 10 ng/ml, and all patients with transitional carcinoma had preoperative CEA values > 10 ng/ml. A correlation between CEA levels and resectability of the primary tumor was found. In bladder carcinoma patients, preoperative CEA levels greater than 10 ng/ml are apparently of prognostic value, since all of these patients have died and all of the long-term survivors had levels .ltoreq. 10 ng/ml.