Introduction and Objectives: Sepsis remains one of the dreaded complications of percutaneous nephrolithotomy (PCNL). To analyze prospectively the preoperative and intraoperative factors that predict the occurrence of systemic inflammatory response syndrome (SIRS) in patients undergoing PCNL so that we can aggressively manage those patients from the preoperative period itself and avert the dangerous complications. Materials and Methods: A prospective study was carried out between Septembser 2016 and April 2018 including all patients who underwent PCNL. Patients with infected collecting system, synchronous ureteric stones, stents, or percutaneous nephrostomy drainage were excluded from the study. Patients were evaluated with physical examination, urine analysis, urine culture and sensitivity, complete blood count, renal function test, X-ray kidney, ureter, and bladder (KUB), and plain and contrast-enhanced computerized tomography KUB. Patients who developed any two or above of the following in the postoperative period were considered to have developed SIRS. (1) Temperature >100.4°F (38°C) or < 96.8°F (36°C). (2) Pulse rate > 90/min. (3) Respiratory rate > 20/min. (4) White blood cell count > 12,000/ml or < 4000/ml.