OBJECTIVE Fluoroscopy-guided percutaneous nephrolithotomy (PCNL) is procedure of choice for treatment of large urinary tract calculi. This study aimed to investigate the affecting factors on fluoroscopy screening time (FST) and radiation dose (RD) of patients undergoing complete supine percutaneous nephrolithotomy (csPCNL). METHODS Analytic cross-sectional study was performed on 355 patients who underwent csPCNL. The correlation between the FST and RD and patients' demographics, stone characteristics, preoperative, intraoperative and postoperative parameters were assessed. Multivariate regression analysis was used to explore various parameters which affect FST and RD. RESULTS Of all 355 patients, 191 (54.65%) were male and 161 were (45.35%) female with mean age of 48.29 ± 12.38 (16-82) years. BMI was 27.61 ± 4.53 (16.61-39.00) kg/m2. The mean operative time was 45.87 ± 18.29 min with mean FST of 101.72 ± 62.00 s. BMI, operative time, success rate, complications, stone number, and tract number had a significant relationship with FST and RD (P < 0.05). On multivariate analysis, BMI, tract number and success rate were found to be independent predictors for FST and RD. Age, gender, operation side, GFR, target calyx, lithotripsy history, stone opacity, size and site, stone configuration and distribution, and hydronephrosis did not have any correlation with FST and RD (P > 0.05). CONCLUSIONS BMI, success rate and tract number can be significant predictor for FST and RD during csPCNL. Identifying the affecting factors on FST and RD can help the surgeon to minimize the danger of radiation exposure by predicting and preoperative planning.