The aim of the study is to evaluate the efficacy and safety of retrograde intrarenal surgery (RIRS) to treat renal stones in preschool age (<7 years) children. From September 2005 to May 2013, a total of 65 children (31 boys and 34 girls) with 72 renal stones were treated using RIRS. Patients were considered stone-free when the absence of residual fragments was observed on imaging studies. In the presence of residual calculi >4 mm, a second-stage RIRS was performed. The pre-operative, operative and post-operative data of the patients were retrospectively analyzed. A total of 65 patients with a mean age of 4.31 ± 1.99 years (6 months-7 years) were included in the present study. The mean stone size was 14.66 ± 6.12 mm (7-30 mm). The mean operative time was 46.47 ± 18.27 min. In 5 (7.69%) patients, the initial procedure failed to reach the renal collecting system and ended with the insertion of a pigtail stent. The stone-free rates were 83.07 and 92.3% after the first and second procedures, respectively. Complications were observed in 18 (27.7%) patients and classified according to the Clavien system. Post-operative hematuria (Clavien I) occurred in 6 (9.2%) patients, post-operative urinary tract infection with fever (Clavien II) was observed in 10 (15.4%) patients, and ureteral wall injury (Clavien III) was noted in 2 (3%) patients. RIRS is an effective and safe procedure that can be used to manage renal stones in preschool age children.