Introduction: Pelviureteric junction obstruction (PUJO) is the most common cause of pathological antenatally diagnosed urinary tract dilatation. Approximately 50% of infants with P3 dilatation on ultrasound scans (USS) will require surgical intervention. This can be approached from either a laparoscopic or open approach in children <10kg, according to surgeon preference. This study compares both approaches outcomes. Methods: Retrospective study (2016-2024) of infants <10 kg with PUJO undergoing Anderson-Hynes dismembered pyeloplasty and >1 year follow-up. Group A included patients that underwent open pyeloplasty, and Group B patients that underwent laparoscopic pyeloplasty. Follow-up included ultrasound ± MAG3. Length of stay (LOS), complication rates (defined as Clavien-Dindo >3, including re-do), and success rates (defined as improved dilatation on USS and absence of symptoms) were compared using a multivariable logistic regression (95% CI). Results: 115 patients were included in the study – 68 patients underwent 72 open procedures and 47 patients underwent 48 laparoscopic procedures. All children had P3 dilatation. The median age, weight, renal function, and LOS were similar in both groups. The median operative time was 88 minutes in Group A and 138 minutes in Group B. The duration of follow up ranged from 12-114 months in Group A and 12-70 months in Group B. Complications occurred in 7% of open cases and 2% of laparoscopic cases, with the majority being stent issues. The majority of patients still had a degree of dilatation on USS but showed overall improvement. 4 patients in Group A underwent re-do surgery, with an even split between flank and dorsal lumbotomy approaches Conclusions: Although the average operating time is longer for children under 10kg undergoing laparoscopic pyeloplasty compared to open, the results are favorable with a lower proportion having complications or requiring redo surgery.