Introduction & Objectives Supine percutaneous nephrolithotomy (PNL) is endorsed as a Level 1a evidence–based option in recent European Association of Urology (EAU) guidelines. Nevertheless, the suitability of supracostal access in the modified supine position remains debated. We undertook a single-centre review to clarify the safety and effectiveness of supracostal PNL in modified supine position for renal stones > 2 cm. Materials & Methods We prospectively analysed 44 consecutive adults who underwent supracostal (11th–12th intercostal space) supine PNL between March 2023 and December 2024. Exclusion criteria were age < 18 years, solitary kidney, organomegaly, pulmonary/pleural disease, active urinary-tract infection, morbid obesity , uncontrolled HTN or DM or major renal/ureteric anomalies. Pre-operative work-up comprised history, examination, serum/urine investigations, and non-contrast CT. Operative metrics (puncture site, operative and fluoroscopy times, haemoglobin drop), postoperative course, and 24-h and 4-week imaging outcomes were recorded. Complications were graded by Clavien–Dindo. Results Mean patient age was 36 ± 9 years (range 18–54) with a male:female ratio of 24:20; the mean BMI was 28.3 ± 2.8 kg m⁻². Calculi measured 27.4 ± 1.9 mm (mean density 987 ± 150 HU). Mean operative and fluoroscopy times were 65 ± 13 min and 1.7 ± 0.4 min, respectively. Haemoglobin fell from 12.6 ± 0.9 to 11.8 ± 1.0 g dL⁻¹, and mean hospital stay was 1.9 ± 0.6 days. The stone-free rate was 77 % at one week and 92 % at four weeks. Ancillary treatment was needed in ten patients—extracorporeal shock-wave lithotripsy in five, second-look PNL in three, and spontaneous fragment passage in two. Thirteen patients (29.5 %) experienced complications: Clavien grade I–II in 11 patients (25 %) and grade IIIa in 3 patients (6.8 %); only two patient (4.5 %) required thoracostomy. No grade IV or V events occurred. Conclusions Supracostal puncture performed in the modified supine position is a feasible, safe, and effective , yielding high early stone-free rates with acceptable morbidity. Larger prospective series with extended follow-up are warranted to validate these findings and define long-term renal and pulmonary outcomes.