Introduction and Objectives: To assess factors affecting Fluoroscopy Time (FT) during PCNL. Methods: Patients who underwent PCNL from 2010 to 2013 at McGill University Health Centre were included. These cases were performed by 10 Post-Graduate Trainees (PGTs) from Post- Graduate Years (PGY) 4 and 5 under direct supervision of a single endourologist (SA). Patient demographics, personnel variations, stone characteristics including S.T.O.N.E nephrolithometry score and procedural factors were compared to Fluoroscopy time. Results: Out of 185 cases, 103 met our inclusion criteria. The mean age was 55.2 – 1.5 with mean BMI of 26.4 – 0.5 kg/m2 and 60 (58.3%) males. There were 37 (35.9%) cases performed by PGTs from PGY 4 and 66 (64.1%) by PGY 5 PGTs. The mean S.T.O.N.E nephrolithometry score was 7.7 – 0.1, with mean stone volume of 621.7 – 57.6 mm2, mean number of punctures of 2.1 – 0.1, mean number of tracts of 1.2 – 0.04, with tubeless PCNL in 53 (51.5%) cases. The mean FT was 120 – 5 sec, with mean operative time of 102 – 3.5 min and mean length of hospital stay (LOS) of 4.2 – 0.34 days. The overall stone free rate after the primary procedure was 72.8%. PGY level significantly affected FT, where PGY 5 trainees utilized significantly less fluoroscopy than PGY 4 trainees (p = 0.04). In addition, there was a significant correlation between FT and the number of punctures (r = 0.6, p = 0.01), number of tracts (r = 0.4; p = 0.01), number of involved calyces (r = 0.24, p = 0.02) and operative time (r = 0.4, p = 0.01). Conclusions: Number of involved calyces, PGY level, operative time, number of punctures and tracts had a significant effect on fluoroscopy time during percutaneous nephrolithotomy (PCNL). Source of Funding: Fonds de la Recherche en Sante´ du Que´bec (FRSQ).