Objective: To assess the safety and efficacy of retroperitoneoscopy technique-assisted percutaneous nephrolithotomy (PCNL) used in the treatment of complexity horseshoe kidney (HSK) with renal stones. Methods: Between January 2012 and April 2015, 5 patients with renal stones in complexity HSK underwent retroperitoneoscopy technique-assisted PCNL. The perioperative data analyzed, included operation time, blood loss, incidence of complication rate, the stone free rate (SFR), and so on. Results: All the patients successfully completed the operation without need for an open surgery. The mean operative time in which this procedure was done was 77.5 +/- 20.6 min, the mean hemoglobin that was reduced was 2.5 +/- 0.8 g/dl, the mean time to remove nephrostomy tube and retroperitoneal tube were 3.0 +/- 1.0, 3.5 +/- 1.0 days, respectively. The mean hospital stay was 7.0 +/- 1.5 days. The SFR of all the patients was 80% (4/5). One patient who had residual stones (6 x 5 mm) in the middle pole underwent additional shock wave lithotripsy after the operation and no serious perioperative complications were noticed. Study limitations include small sample size and short follow-up time. Conclusions: Retroperitoneoscopy technique-assisted PCNL is a feasible, safe, and an effective alternative to laparoscopic pyelolithotomy for treating complexity HSK with renal stones, especially in a situation where the HSK is tightly wrapped by the surrounding organs. (C) 2016 S. Karger AG, Basel