Abstract To evaluate the safety and efficacy of robotic-assisted laparoscopic pyeloplasty (RALP) in infants under 6 months of age with ureteropelvic junction obstruction (UPJO). A retrospective analysis was conducted on infants aged ≤ 6 months who underwent RALP for UPJO between March 2021 and June 2024. Surgical indications included ultrasonographic evidence of severe hydronephrosis, progressive postnatal hydronephrosis, or symptoms related to hydronephrosis compression. Data on demographic characteristics, surgical details, postoperative complications, and follow-up outcomes were analyzed. Among 52 infants (34 male, 18 female), the median age was 70 days (IQR: 45, 107; 95% CI: 61, 87) and mean weight was 5.90 ± 1.39 kg (95% CI: 5.5, 6.3). All procedures were completed robotically without conversion. The mean operative time was 189 ± 34 min (95% CI: 177, 197) with median blood loss of 8.5 mL (IQR: 6.4, 11.3; 95% CI: 7.7, 9.7). Double-J stent placement (4.7 F) was successful in all cases. The median hospital stay was 4.0 days (IQR: 3.0, 4.0; 95% CI: 3.0, 4.0). Postoperative complications occurred in 7 patients (13.5%), including Clavien-Madadi grade I (n = 2), II (n = 4), and III (n = 1). At 3-month follow-up, the mean anteroposterior diameter (APD) decreased from 30.6 ± 8.6 mm to 11.8 ± 6.8 mm (P