Background: In order to prevent infectious complications following endourological procedure of upper urinary tract stones, it is essential to determine which patients are at high risk of developing this complication. We aimed to identify predictors that may cause systemic inflammatory response syndrome (SIRS) after the endourological procedure of upper urinary tract stones. Materials and Methods: Patients who underwent percutaneous nephrolithotomy (PNL), flexible ureteroscopy (F-URS), or semirigid ureteroscopy (SR-URS) in our center between January 2011 and June 2020 were evaluated retrospectively. After surgery, patients were pursued for SIRS criteria. Logistic regression analyses were applied to identify predictors of SIRS. Results: A total of 1471 patients were included in the study. The rates of SIRS after PNL, F-URS, and SR-URS were 12.9%, 6.3%, and 1.7%, respectively. In multivariate analysis, predictors for SIRS were determined to be stone volume, operative time, and history of recurrent urinary tract infection (UTI) in the PNL group; ipsilateral stone surgery history, stone volume, and operative time in the F-URS group; and stone volume, operative time, and history of recurrent UTI in the SR-URS group. Conclusion: Stone volume and operative time were determined to be independent predictors of SIRS in endourological surgery of upper urinary tract stones.