An indwelling ureteral stent is commonly used for relief of ureteral obstruction. However, few reports have documented the frequency of febrile urinary tract infection and changes in renal function in patients with long-term ureteral stent placement. Here we report our experience with patients who had undergone long-term placement of ureteral stents. Between January 2005 and March 2011, we performed exchange of ureteral stents in 25 patients for more than one year. The mean serum creatinine level at the baseline, after stent placement, and 1 year later was 2.10, 1.24, and 1.39 mg/dl, respectively. In 14 of the patients, 39 episodes of febrile urinary tract infection occurred. Among a total of 1,055 stent exchanges, 39 episodes (3.7%) of stent encrustation occurred. Two patients in whom stents had been forgotten suffered septic shock. The serum creatinine level following a long placement period did not change significantly, and of the patients whose hydronephrosis remained after stent placement, the risk of febrile urinary tract infection rises. Our results suggest that ureteral stents could be indwelt for a fairly long period of time without major complications as long as they were carefully followed up and regularly exchanged.