Objectives: To evaluate the feasibility, operative time, efficacy and safety of the modified lateral position in percutaneous nephrolithotomy (PCNL) for renal calculi, comparing it with the standard prone position PCNL. Material and Method: The patient is placed with the thorax in the lateral position and the pelvis in an oblique position. Then the lower limbs are split and bent in the lowest position. Initial placement of a retrograde ureteral catheter, tract formation, stone fragmentation and retrieval, and optional extra procedures were accomplished with the patient in the same position. Results: The study comprised 82 patients; 29 in split-leg modified lateral position (SL-MLP) group and 53in conventional prone position (PP) group. Three patients (all in PP group) underwent sequential bilateral percutaneous nephrolithotomy (PNL) during the study period and each procedure was considered as an independent case. So, the studied cases, according to the number of PNL procedures, were 85; 29 in SL-MLP group and 56 in PP group. Conclusions: split-leg modified lateral position in percutaneous nephrolithotomy (SL-MLP PNL) has significantly lower operative time compared with conventional PP PNL. The stone free rate, need for ancillary procedures and complication rate were equal in both groups.