Adenocarcinoma of the urinary bladder, including urachal carcinoma, is a rare tumor with incidence in the range between 0.5% and 2.2% of all epithlial bladder neoplasms. Ten cases of adenocarcinoma of the urinary bladder(eight cases of promary adenocarcinoma and two cases of urachal carcinoma) are presented. We described the computed tomography (CT) appearances of adenocar-cinoma of the urinary bladder and tried to find out the characteristic CT findings of urachal carcinoma. CT scans were evaluated for the location of the tumors, presence of calcification in the tumor, and the tumor extension. Seven tumors were located at the dome of the bladder(70%), two were at lateral walls, and one was at anterior wall. Seven were single mass and three were multicentric masses in the bladder. Fine punctate calcifications scattered within the tumors were detected in four cases(40%); three of the eight, primary adenocarcinoma, and one of the two, urachal carcinoma. Two urachal carcinomas we e characterized by midine position and predominantly extravesical growth along the urachus. Gross extravesical extension with distant metastasis were presented in seven cases(70%) at the time of initial diagnosis. CT may be useful in evaluating the adenocrcinoma of the urinary bladder and differentiating urachal carcinoma from bladder cancer.