Carcinoembryonic antigen (CEA) is elevated in urine and/or serum of patients with transitional cell carcinoma (TCC) of the urinary bladder. A group of 26 patients with TCC of the urinary bladder were evaluated with regard to urine/serum CEA levels and CEA tissue content. CEA could be detected in normal, metaplastic and pre-neoplastic urothelium as well as tumor tissue. CEA was mainly localized on cell membranes, but with increasing tumor malignancy and infiltration a shift to cytoplasmatic localized CEA was noted. There was also a decrease in CEA content in the latter group. CEA urine levels were elevated above normal in more advanced tumor stages; however, the values varied greatly between individuals. All serum levels were within normal limits. No correlation could be established between urine/serum CEA levels and CEA tissue content.