ObjectivesTo assess and compare the effectiveness and safety of flexible ureteroscopy (f‐URS) with a novel flexible ureteral access sheath (f‐UAS) versus mini‐percutaneous nephrolithotripsy (mini‐PCNL) in treating 2–3 cm renal stones.MethodsRetrospectively analyzed consecutive cases that underwent f‐URS with f‐UAS (12/14 Fr) from January 29, 2022, to November 30, 2022. Consecutive cases that underwent mini‐PCNL (18 Fr) from June 5, 2021, to January 26, 2022, were selected as controls. The f‐UAS is a novel device with a 10 cm anterior tip that passively bends along with the f‐URS to enter the renal calyx. We analyzed demographic characteristics, stone parameters, operative time, stone‐free rates (SFR), hospitalization time, and complication.ResultsA total of 96 consecutive cases that underwent f‐URS with f‐UAS and 96 consecutive cases that underwent mini‐PCNL were included in the study. There were no significant differences between the two groups in terms of operative time (p = 0.06), stone volume clearance (p = 0.533) and complete SFR (p = 0.266) on the first postoperative day or residual Stone after 1 month (p = 0.407). We observed a significantly shorter postoperative hospital stay (1.4 days vs. 2.1 days; p < 0.001) and a lower decrease in hemoglobin levels (0.39 g/dL vs. 0.68 g/dL; p < 0.001) in the f‐UAS group. The mini‐PCNL group had a significantly higher overall complication rate (13.5%) compared with the f‐UAS group (5.2%; p = 0.048).ConclusionsIn the treatment of 2–3 cm renal stones, f‐URS with a novel f‐UAS may provide a superior alternative to mini‐PCNL, potentially challenging its established status.