Correct staging of the vesical cancer is very important in assessing of prognosis and therapy planning. For evaluation of significancy and accuracy in determination of staging by computed tomography, authors performed comparative study between preoperative computed tomographic staging using TNM classification and pathological staging in 20 cases of pathologically proven vesical cancer. The overall accuracy of CT staging using TNM classification in 20 cases with pathologically confirmed vesical cancer staging was 80% and detecting rate of lymphadenopathy was 90%, sensitivity was 85.7%, and specificity was 92.3. The rate of overstaging by CT scan was 15% (3/20) and understaging was 5% (1/20). The causes of overstaging were misinterpretation of the previous inflammatory process or postbiopsy perivesical fibrosis as perivesical tumor growth and dilated and engorged vessels as lymphadenopathy. Non-detection of small sized lymph node was the cause of understaging The major role of C was in demonstrating extension of tumor outside the urinary bladder, so CT scan should be performed before biopsy and additional CT scan with position change is also helpful in equivocal case.