Background/aim: Nonalcoholic fatty liver disease (NAFLD) is known as the most common cause of chronic liver disease. It is accepted that the leading cause of death in patients with NAFLD is from coronary events. Blood urea nitrogen (BUN) was used as a prognostic indicator for cardiovascular disease. We aimed to investigate the relationship between BUN levels and metabolic, biochemical, and histopathologic findings of nondiabetic patients with NAFLD. Materials and methods: A total of 195 male patients with biopsy proven NAFLD and 82 healthy controls with normal liver and renal function tests and normal abdominal ultrasonography were enrolled in the study. BUN levels were reviewed retrospectively. Results: The mean BUN levels of patients and controls were 13.07 (11.3?15.41) and 13.31 (10.97?15.87) mg/dL respectively. Patients were grouped as simple steatosis (n = 33, 16.9%), borderline nonalcoholic steatohepatitis (n = 64, 32.8%), and nonalcoholic steatohepatitis (n = 98, 50.3%), and the BUN levels of the histologic subgroups were 13.14 ± 2.89, 14.34 ± 3.04, and 13.71 ± 3.21 mg/dL, respectively. We could not find any differences between the patient group and control group with respect to BUN levels. Conclusion: Our findings showed that there was no relationship between BUN levels and metabolic, biochemical, and histopathologic findings of patients with NAFLD. Further investigations, including in patients with late stages of NAFLD, are required.