Purpose <p>Today, disposable flexible ureteroscopes are increasingly used in retrograde intrarenal surgery (RIRS) as an alternative to reusable flexible ureteroscopes. The comparison of the safety and effectiveness of these two devices is still a matter of debate. This study evaluates the efficacy and safety of disposable-flexible ureteroscopes vs reusable flexible ureteroscopes in RIRS.</p> Materials and methods <p>The study included 1165 RIRS cases, and the patients were divided into two groups. Group 1 consisted of cases with reusable RIRS, 838 in total, while Group 2 consisted of disposable RIRS cases, 327 in total. Due to significant differences, case–control matching was performed, and subsequently, there were 229 patients in both groups. The demographic and clinical data of patients, stone characteristics, surgical data, perioperative and postoperative complications, postoperative urinary tract infection&#xa0;rate, duration of hospitalization, and stone-free rates (SFR) were analyzed and compared.</p> Results <p>No demographic differences were observed between the two groups after case–control matching. While operative time, SFR, and postoperative infection rates were similar between the groups (<i>p</i> &gt; 0.05), fluoroscopy (<i>p</i> = <b>0.001</b>) and hospitalization (<i>p</i> = <b>0.029</b>) times were statistically significantly lower in the disposable ureteroscopy group. Perioperative and postoperative complications were also lower in this group (<i>p</i> = <b>0.018</b> and <i>p</i> = <b>0.001</b> respectively).</p> Conclusion <p>Our research indicates that single-use ureteroscopes are a strong alternative to reusable ureteroscopes, demonstrating similar efficacy and reduced complication rates in the treatment of upper urinary tract stones.</p>