Purpose Sparse published data exist on the impact of preexistent ureteral stents on the success of ureteroscopic stone surgery. We investigated the impact of a preexistent ureteral stent in relation to a number of parameters and outcomes of ureteroscopic management for urinary lithiasis. Materials and Methods We retrospectively evaluated a cohort of patients undergoing ureteroscopy for renal and ureteral calculi. Data were abstracted on stone side, size, number and site, patient demographics, total stone burden, ureteral access sheath use, preoperative ureteral stent, ureteroscope type and outcome. Statistical analysis was done. Results The success rate of 1 and 2 ureteroscopic procedures was 86.9% and 97.3%, respectively. Primary analysis included data on 221 initial procedures. The single procedure success rate for stone site was 91.9% for the distal ureter, 89.7% for the proximal ureter, 83.3% for the renal pelvis, 80.5% for the lower pole and 82.4% for the interpolar/upper pole. Success was negatively associated with primary stone size (p = 0.020), total stone number (p = 0.001) and cumulative stone burden (p <0.001). Stone site was not a predictor of success (p = 0.394). A preexistent stent was positively associated with success but it was not statistically significant (adjusted OR 2.22; 95% CI 0.88, 5.63; p = 0.254). Secondary analysis in patients who initially underwent flexible ureteroscopy yielded results consistent with those of primary analysis. Conclusions Results show that ureteropyeloscopic lithotripsy and stone extraction may be performed with a high success rate. Success was significantly inversely related to stone size, cumulative stone burden and number of stones. Success was positively related to a preexisting ureteral stent but not significantly so.