Purpose To investigate the incidence and pathologic characteristics of prostate cancer (PCa) incidentally discovered at the time of radical cystectomy and its impact on overall survival. Materials and Methods A single center retrospective study of 762 male patients who underwent radical cystoprostatectomy from Jan 1994 to Dec 2012. Results Of all included patients, 132 (17.3%) were found to have PCa. Patients with incidental PCa had a significantly higher mean age (69.2 vs. 62.2 years, P=0.015). Among the 132 patients with PCa, prostate specific antigen (PSA) analysis was available in 76 patients (57.6%), with a median value of 1.06ng/mL, and 61 (80.3%) patients had a PSA value below 4ng/mL. Four hundred and thirty-six patients (57.1%) were successfully followed, with a median duration of 46.5 months. The overall 5-year survival rate was 62.1%, and the 5-year cancer–specific survival rate was 72%. PCa recurrence was defined by two consecutive PSA values of >0.2 ng/mL and rising, and no PCa recurrence occurred. According to a univariate analyses, incidental PCa was not associated with cancer-specific survival (P=0.192) or overall survival (P=0.493). According to univariate analyses, the overall survival of patients with PCa was not associated with prostate cancer staging, PSA value, or Gleason score (All P values>0.05). Conclusions Prostate cancer incidentally discovered at the time of radical cystectomy does not decrease overall survival. Patients with incidental PCa were older than those without. The PSA value before operation is not helpful for predicting incidental prostate cancers.