ObjectiveTo compare the outcomes of retrograde flexible ureteroscopy (fURS) with retroperitoneal laparoscopic ureterolithotomy (RLU) for large proximal ureteric stones.Patients and MethodsA prospective randomised trial was conducted from January 2018 through December 2022 including patients with impacted proximal ureteric stones of 15–25 mm. Patients underwent fURS or RLU. Primary outcome was the stone‐free rate. Demographic data, stone features, and complications rates were also compared between groups.ResultsA total of 64 patients were enrolled, 32 in each group. The mean impacted stone time was similar between groups, as well as stone size (17 mm) and stone density (>1000 Hounsfield Units). The ureteric stone‐free rates between the two groups (93.7% in fURS vs 96.8% in RLU; odds ratio [OR] 0.72, 95% confidence interval [CI] −1.72 to 3.17; P = 0.554), and overall success rates, which take into account residual fragments in the kidney (84.3% in fURS vs 93.7% in RLU; OR 1.02, 95% CI −0.69 to 2.74; P = 0.23), were similar. Operative time was also not statistically significantly different between groups (median 80 vs 82 min; P = 0.101). There was no difference in hospital length of stay. Retropulsion rate was higher with fURS (65.6% vs 3.1%; p < 0.001). Residual hydronephrosis (34.3% each group) and complication rates did no differ according to treatment.ConclusionFlexible URS and RLU are both highly efficient and present low morbidity for large impacted proximal ureteric stone treatment. RLU is not superior to fURS.