ABSTRACT Objective To examine the the effect of body mass index (BMI) on PNL results and complications with a large number of patients. Materials and Methods A total of 958 patients were included in the study, who underwent percutaneous nephrolithotomy in our clinic between 2008 and 2015. Patients were divided into 2 groups according to their body mass index. Patients with a BMI < 30 kg/m2 were classified as group 1 (n:676) and patients with a BMI ≥ 30 kg/m2 were classified as group 2 (n:282). Achieving stone-free status or having residual stones of ≤ 4 mm were considered as operational success. Results The mean age was 47.9 years for group 1 and 48.9 years for group 2 patients. At postoperative first month CT analysis, residual stone was not observed in 466 patients (69%) of group 1 and 20 (72%) patients of group 2. There was no significant difference between the groups in terms of stone-free status (p=0.348). There was no significant difference between two groups complications. Also, there was no difference between the groups for requiring additional intervention (p=0.924). No other complications were observed in the patients. Conclusions BMI does not affect the outcomes of percutaneous nephrolithotomy as well as complication rate.