Ureteroscopic lithotripsy has higher stone free rate compared with extracorporeal shock wave lithotripsy. Ureteroscopyassociated complications are flank pain, transient hematuria, ureteral perforation, ureteral avulsion, and sepsis. Among these, sepsis is most serious complication with the incidence of about 1%. We report a case of sepsis and septic shock that developed immediately after ureteroscopic lithotripsy. It was diagnosed with elevated lactate and procalcitonin values. It was caused by Pseudomonas aeruginosa which was detected in preoperative urine culture and postoperative blood culture.