Abstract Ureteroscopic procedures are being commonly performed in urology, but only a few clinical studies have been conducted on infectious complications after these procedures, and overall understanding on the preoperative use of prophylactic antibiotics is insufficient. This study examined the incidence rate of infectious complications and the risk factors affecting incidence after ureteroscopic procedures. We retrospectively reviewed the medical records of 531 patients who underwent ureteroscopy and ureteroscopic lithotripsy in our hospital, including age, sex, past history, comorbidity, urine analysis, urine culture, blood test, hydronephrosis, urethral catheter or ureteral stent, and percutaneous nephrostomy placement from January 2002 to December 2011. A total of 20 patients (3.8%) contracted infectious complications after various procedures in the upper urinary tract. Preoperative bacteriuria, hydronephrosis, and the placement of a urethral catheter or ureteral stent, and percutaneous nephrostomy are significant risk factors of infectious complication. No significant differences were shown in the types and start time of prophylactic antibiotics. Diagnostic ureteroscopy exhibited a higher incidence rate of infectious complications compared to ureteroscopic lithotripsy.