Objectives: The relation between non-functioning adrenal adenoma and unfavorable metabolic status has been a debate so far. We aimed to demonstrate the prevalence of non-alcoholic fatty liver disease (NAFLD) in subjects with silent adrenal adenomas. Materials and Methods: 130 consecutive subjects with non-functioning adrenal adenomas, 170 age-, gender- and BMI-matched individuals without adrenal gland disorders, and 20 patients with Cushing's syndrome were included in the study. Fatty liver disease was diagnosed by ultrasonography and the severity was scored semiquantitatively. Liver function tests were performed. Cushing's syndrome and non-functioning adrenal adenoma were diagnosed using appropriate tests of hypothalamus-pituitary-adrenal function. Results: The prevalence of NAFLD was 30.7%, 65.0% and 39.4% in adenoma group, Cushing's syndrome group and control group, respectively. There was no significant difference in terms of Type 2 diabetes mellitus, hypertension and NAFLD prevalence between adenoma group and controls. NAFLD was not only more common in subjects with Cushing's syndrome but was also more severe. Hypercortisolemia strongly predicted the development of metabolic syndrome (OR: 10.571, p=0.004). When age, gender, hypercortisolemia and metabolic syndrome were assessed, metabolic syndrome remained as the sole independent predictor of fatty liver development (OR: 9.162, p<0.001). Conclusion: Comparable prevalence between adenoma and control group was likely to be associated with similar rates of metabolic derangements and similar BMI. Cortisol excess seemed to be related with fatty liver development mainly through its unfavorable metabolic effects.