Laparoscopic pyeloplasty for the treatment of ureteropelvic junction obstruction (UPJO) in children is still one of the most demanding operations in urology. We report on a 12-year-old boy with UPJO in a duplicated collecting system with high ureter fissus. He was admitted with a 1-year history of recurrent flank pain and dilation of the lower duplicated collecting system. We performed a retroperitoneoscopic Anderson-Hynes pyeloplasty.