We report the technique and outcomes of immediate robot-assisted ureteral reimplantation due to unexpected ureteral injury during robot-assisted laparoscopic prostatectomy (RALP). A 61-year-old male was diagnosed with locally advanced prostate adenocarcinoma (T3bN0M0). Multiple positive margins at the bladder neck were noted on frozen section during RALP, and re-excision of the bladder neck was done. Unfortunately, the distal third of right ureter was transected. We immediately performed robot-assisted ureteroneocystostomy with double J stent insertion. No complications developed during the follow-up period.