Objectives: To report on long-term follow-up and outcomes of infants and small children who have undergone laparoendoscopic single-site (LESS) partial nephrectomy to manage upper urinary tract duplication and fusion anomalies. Materials and Methods: A retrospective review was performed evaluating outcomes of pediatric patients who underwent LESS partial nephrectomy for upper urinary tract duplication and fusion anomalies from January 2012 to July 2015, by a single surgeon at a tertiary pediatric referral center. Demographic and perioperative data were reviewed as well as follow-up imaging. Descriptive statistics were used for analysis. Results: A total of 18 patients were identified. Additional access was used for two patients to complete the procedure. Median follow-up was 39 months. No short-term complications were encountered. Three patients were noted to have abnormal postoperative ultrasounds: two perinephric fluid collections and one atrophy of the remaining ipsilateral moiety. One fluid collection resolved completely, and the other decreased in size. Complete atrophy of the ipsilateral moiety occurred. No secondary procedures were required. Conclusions: LESS partial nephrectomy is safe for renal duplication and fusion anomalies with good long-term outcomes. Although it can be safely performed, it is a technically demanding procedure and has been discontinued in favor of robotic partial nephrectomy.