ABSTRACTPurposeBladder endometriosis (BE) accounts for 84% of cases of urinary tract involvement. The use of cystoscopy for preoperative evaluation is limited. The aim of this study was to evaluate the accuracy of preoperative dynamic cystoscopy (DC) in patients undergoing surgery for deep endometriosis and to describe the main findings and their impact on surgical planning.Materials and MethodsThis cross-sectional observational study was conducted from January 2011 to March 2022. DC findings were divided into two groups according to the depth of involvement. To estimate sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), laparoscopic findings of bladder involvement and histopathological report were used as the gold standard.ResultsWe included 157 patients in this study. 41 had abnormalities in DC. Of these, 39 had abnormalities that were confirmed intraoperatively. The sensitivity and specificity of the test were 58.21% and 97.78%, respectively. PPV was 95.12%, and NPV was 75.86%. The presence of any lesions in the DC had a diagnostic odds ratio (OR) of 61.28 for BE. Patients with BE type 2 had a higher rate of partial cystectomy than those with BE type 1 lesions (OR 9.72 CI 95% 1.9-49.1)ConclusionDC appears to be a highly specific test with lower sensitivity. DC abnormalities are associated with a higher ratio of bladder surgery for the treatment of deep endometriosis, and BE type 2 seems to be associated with a greater ratio (9.72) of partial cystectomy.