Introduction: Percutaneous Nephrolithotomy (PCNL) has been demonstrated as highly efficacious for treatment of large or staghorn pyelocalyceal stones in pediatric patients. In this prospective study, we used the GMSV position to simultaneously treat ureteric and ipsilateral renal stones by retrograde ureteroscopy and supine PCNL in children. Materials & Methods: We prospectively performed retrograde ureteroscopy and supine PCNL in children with ureteric stones and ipsilateral renal calculi from Jan 2020 to May 2023. Inclusion criteria were: age younger than 18 years, Presence of ipsilateral ureteric calculi and renal calculi. Exclusion criteria included contraindications to general anaesthesia and different illnesses such as coagulation abnormalities. All procedures were performed with the patient in the supine Valdivia modified Galdakao position. Results: A total of 39 children (23 males and 16 females) presenting with symptomatic ureteric and ipsilateral renal calculi underwent retrograde ureteroscopy and supine PCNL in a single setting. Mean age was 14 years. Mean operating time was 95 mins. Mean drop in hemoglobin following the procedure was 0.5 gm%. Our initial stone clearance rate with combined ureteroscopy and PCNL was 84.6% and following SWL for residual fragments stone clearance was 100% in all children at 3 months follow-up. Conclusion: In this study we have been able to tackle both ureteric calculi and ipsilateral renal calculi in a single setting using the GMSV position in children. The combined procedure of ureteroscopy and ipsilateral PCNL in GMSV position is feasible, safe and effective and is associated with minor postoperative complications.