Background <p>Retrograde intrarenal surgery (RIRS) is increasingly used for management of renal calculi. Many predictive scores have been devised to predict stone-free rate (SFR) after RIRS including Ito’s nomogram. The aim of this study is to evaluate preoperative parameters that affect SFR after RIRS to help with patient counselling.</p> Methods <p>Patients with renal stones up to 30&#xa0;mm in greatest diameter were recruited. They were offered RIRS via disposable flexible ureteroscopy and Holmium laser fragmentation. Ito’s score was calculated for each patient preoperatively to estimate post-operative SFR. Also, other factors as stone Hounsfield units (HU), pre-stenting, and access sheath use were recorded.</p> Results <p>A total of 80 patients met the inclusion criteria. Median stone volume was smaller in cases that were stone free (532.4 vs 748.0&#xa0;mm³, <i>p</i> = 0.076). Patients with residuals had higher rates of multiple (61.5% vs 16.7%, <i>p</i> &lt; 0.001) and lower pole (61.5%vs 37.0%, <i>p</i> = 0.039) calculi. Hydronephrosis, operator experience, HU, access sheath use, pre-stenting, and total Ito score were not significantly different between stone-free patients and patients with residuals. Multivariate logistic regression showed that presence of multiple renal stones (<i>B</i> = 0.158, <i>p</i> = 0.002) is the only significant predictor of SFR.</p> Conclusion <p>Larger stones, stones in the lower pole, and especially multiple renal stones have higher rates of residual stones after RIRS. This should be clarified to patients during preoperative decision-making and discussion about RIRS and its alternatives’ pros and cons has to take place prior to surgery.</p> <p><i>Trial registration</i>: Trial registered at clinicaltrial.gov, under number NCT05857501 on May 10th, 2023. <a href="https://clinicaltrials.gov/study/NCT05857501">https://clinicaltrials.gov/study/NCT05857501</a>.</p>