Introduction:Renal stones are a common pathology in daily practice with a continuously increasing incidence. Using flexible ureteroscopy (fURS), urologists can treat difficult renal stones through the natural orifice and maintain a satisfactory stone-free rate. Even though advancing technologies offer the opportunity for minimally invasive surgery, the surgeon is still exposed to a considerable amount of ionizing radiation during several procedures. In this study, the aim is to determine the efficacy of flexible ureteroscopy without fluoroscopy in terms of stone-free rates and complications. Materials and methods:In the Urology Department of Saint John Clinical Emergency Hospital in Bucharest, Romania, a retrospective study was conducted on 98 patients diagnosed with renal calculi between September 2020 and December 2021. Using two different groups, the demographic characteristics of patients, characteristics of stones (size, number, location), the use of fluoroscopy, the operative time (in minutes) and postoperative complications, and the stone-free rate were compared. In one of the groups, fluoroscopy was used during fURS (Group I), while in the second group (Group II), no ionizing radiation was used during fURS. Results:Twenty-four males and 23 females were enrolled in Group I, whereas 31 males and 20 females were enrolled in Group II. The mean age of subjects was 63.2 years old in the fluoroscopy group and 61.6 years old in the group without fluoroscopy. While the stone characteristics revealed some variations in stone location between the compared groups, there were no statistical differences in mean stone diameter (1.489 mm - Group I vs. 1.588 mm - Group II). Stone-free rates and complications classified using Clavien-Dindo modified system for urological surgeries were used to analyze the main results. Group II had a slightly higher stone-free rate, but statistical studies found no significant differences; therefore, both methods are deemed equal in this field. Identified complications were classified as Clavien I and II and were successfully treated for both groups. Conclusion:This study reveals that by adhering to additional intraoperative measurements for guiding the access sheath, fURS without fluoroscopy can be performed safely and with a high success rate.