Tissue polypeptide antigen (TPA) both in normal and neoplastic urinary bladders has been studied by immunocytochemistry. A comparison of TPA with epithelial membrane antigen (EMA), keratins and carcinoembryonic antigen (CEA) in various tumor grades and stages has been performed better to define TPA role in bladder carcinomas. Well-differentiated tumors were strongly stained for TPA with a uniform staining intensity. Undifferentiated tumors were weakly stained for TPA with an uneven staining intensity. There was no relation between TPA findings and stages of invasion. However, TPA seems to be a very helpful diagnostic tool for tumor grading and staging.