Acute urinary retention (AUR) is associated with hormone imbalance in men. However, limited studies focused on exploring the complications of AUR in patients with prostate cancer (PC) who receive androgen deprivation therapy (ADT). Therefore, we aim to evaluate the subsequent risk of AUR in ADT-treated PC patients. We collected data from 24,464 male patients who were newly diagnosed with prostate malignancy from a longitudinal health insurance database of catastrophic illness in 2000 to 2008. All PC patients were categorized into 2 cohorts, namely, ADT cohort and non-ADT cohort, based on whether or not the patient receives ADT. The patients were followed up until the occurrence of AUR. Multivariate Cox proportional hazard regression and Kaplan-Meier analysis were performed. After a 12-year follow-up, the incidence rates of AUR were 12.49 and 9.86 per 1000 person-years in ADT and non-ADT cohorts, respectively. Compared with the non-ADT cohort, the ADT cohort had a 1.21-fold increase in AUR risk based on the adjusted model (95% CI = 1.03-1.43). In addition, PC patients receiving early ADT treatment within 6 months or receiving only luteinizing hormone-releasing hormone treatment also had significantly increased risk of AUR. ADT was positively associated with AUR risk. PC patients receiving ADT should be informed about the risks of bladder outlet obstruction and AUR, and they may benefit from screening for related risk factors. New guidelines and treatments should be proposed in the future to manage ADT-related lower urinary tract symptoms and reduce the risk of AUR.