Purpose: We assess the prevalence of overactive bladder (OAB) and its risk factors in a male urologic veterans population. Materials and Methods: Validated self-administered questionnaire was prospectively given. Results: Among 1086 patients, OAB was present in 75%, of which 48% had not been diagnosed/treated. The risk of OAB increased with age. OAB was not associated with BMI, smoking, race, diabetes, CHF, and COPD. Conclusions: The prevalence of OAB in this population is under-diagnosed and under-treated.