Patients undergoing radical prostatectomy are at increased risk of development of post-operative inguinal hernias (IH). We present the largest series of transperitoneal combined robotic-assisted laparoscopic prostatectomy (RALP) and IH. After IRB approval, data from patients undergoing RALP at two centers were prospectively entered into a database and analyzed. IH were repaired robotically via a transperitoneal route with mesh. Between June 2002 and May 2007, 837 RALPs were performed, 80 of which included combined IH repair (9.6%), by two surgeons, T.A. and D.S. Forty-two patients (52.5%) had IH on pre-operative exam. Twenty-four hernias were left, 32 right, and 24 bilateral. Twenty-two patients had prior ipsilateral or contralateral herniorrhaphy. After dissection of the hernia sac, a swatch of flat Marlex mesh (n = 22), a polypropylene mesh plug (n = 19), an Ultrapro hernia system (n = 7), a Proceed coated mesh (n = 19), a 3D-Max (n = 37), a combination of both umbrella and flat mesh (n = 3), or suture alone (n = 2) was used. Inguinal herniorrhaphy added approximately 15 min of operative time in all cases. There was one hernia recurrence over an average follow-up period of 12.5 months (0.2-52 months). There was one complication attributable to IH repair-a urine leak which was attributed to anastomotic stretch due to reperitonealization. Urological surgeons should perform a thorough inguinal exam during preoperative evaluation and intraoperatively to detect subclinical inguinal hernias. Inguinal herniorrhaphy at the time of RALP is safe and should be routinely performed. © 2007 Springer London.