At present, robot-assisted radical prostatectomy (RARP) is a gold standard in radical prostatectomy. The aim of this study was to evaluate the incidence, risk factors, and timing of occurrence of inguinal hernia (IH) after RARP.We included 427 patients with prostate cancer who underwent RARP by a single surgeon from February 2006 to August 2017. Incidence, clinical, and pathological factors were investigated to assess relationship with the development of IH.Postoperative IH occurred in 29 cases (6.79% of all RARP patients), whereas 22 cases (75.9% of all IH patients) occurred within the first 2 years. The median follow-up period was 5.2 years, and the median age of patients was 65 years. Postoperative IH occurrence was significantly associated with body mass index (BMI), smoking history, and low surgeon experience (P = .036, .023, and .048, respectively). However, low surgeon experience did not reach statistical significance after multivariate analysis.The overall incidence of IH after RARP was significantly associated with BMI and smoking history. With obvious incidence of IH within the first 2 years after operation which was not observed at the open prostatectomy, RARP itself may play a role in the development of IH.