Background Retrograde ureteroscopy as a minimally invasive treatment of ureteral calculi can be complicated by the occurrence of urinary tract infections. Fever is considered the main indicator of such postoperative complications and we aimed to study its incidence in patients with and without preoperative antibiotic prophylaxis.Methods We included all patients who underwent retrograde ureteroscopy for ureteric stones in the Iași and Tg Mureș Urology Clinics from 2009 to 2012. Data were statistically analyzed using the EpiInfo 7 software. Indicative of a statistically significant difference was a p value <0.05.Results We recorded fever in a total of 108 cases, accounting for 22.83% of all subjects in the study. Group 1 included patients who received antibiotic prophylaxis; 48 of 147 (32.65%) were febrile, compared with Group 2 (no antibiotic prophylaxis), where we recorded febrile syndrome in 60 (18.40%) cases, p=0.0009. Comparing the two groups based on calculus size, for stones with diameters of 0.6-0.8 cm 38.71% of patients were febrile in Group 1, compared with 10.88% in Group 2 (p=0.0008). Secondary ureterohydronephrosis did not statistically influence the frequency of fever in any of the studied groups.Conclusion Less than half of all febrile patients had positive urine cultures, which may point to other causes, such as noninfectious factors (aseptic kidney inflammation). This study did not prove the efficiency of preoperative antibiotic prophylaxis; however, based on the clinical experience of the past 120 years, infectious complications are known to be associated with urological maneuvers and prophylaxis could be indicated.