The hypothalamic-pituitary-adrenal (HPA) axis seems to play an important role in obesity and Type 2 diabetes (DM). The aim of the present study was to determine the adrenal volume in obese patients with DM in comparison to obese non-diabetic patients. Eleven diabetic obese and 19 non-diabetic obese women were sequentially invited to take part in the study. Computed tomography (CT) scan of the abdomen was performed to determine adrenal volume, visceral (VF) and sc fat (SCF). Daily urinary free cortisol (UFC) was used as a measure of integrated cortisol production. In the diabetic patients, hemoglobin A1c was measured as an index of metabolic control. Compared to nondiabetic controls, patients with diabetes had a significantly higher total adrenal volume (4.29+/-1.50 vs 2.95+/-1.64; p=0.03). A highly significant correlation was detected between VF and VF/SCF ratio and total adrenal volume in the whole group (r=0.36, p=0.04 and r=0.48, p=0.008, respectively). This study, therefore, suggests an association between abdominal obesity, enlarged adrenals and Type 2 diabetes. These findings support the hypothesis that an increased activity of the HPA axis in obese subjects may be involved in the pathogenesis of Type 2 diabetes.