Introduction: Percutaneous nephrolithotomy is an efficient approach for treatment of different types of kidney stones. Various types of access techniques have been described like sequential dilatation and one-shot procedure.

Objective: To determine the differences in time of exposure to X-rays and hemoglobin levels between techniques.

Methods: Controlled clinical trial. Patients older than 18 years with complex/uncomplicated kidney stones, without urine infection were included. They were assigned randomly to one of the two techniques. Response variables were determined before and 24 h after procedures.

Results: 59 patients were included: 30 underwent one-shot procedure (study-group) and 29 sequential dilatation (control-group). Baseline characteristics were similar. Study group had a lower postoperative hemoglobin decline than control group (0.81 vs. 2.03 g/dl, respectively; p < 0.001); X-ray exposure time (69.6 vs. 100.62 s; p < 0.001) and postoperative creatinine serum levels (0.93 ± 0.29 vs. 1.13 ± 0.4 mg/dl; p = 0.039). No significant differences in postoperative morbidity were found.

Conclusion: One-shot technique demonstrated better results compared to sequential dilatation.