Emerging evidences indicate that patients diagnosed with adrenal incidentaloma may present with cardiovascular complications. Epicardial fat is known to play a role in left ventricle (LV) changes. Whether epicardial fat can be associated with LV mass (LVM) in patients with incidentaloma is unknown. We test the hypothesis that echocardiographic epicardial fat thickness is independently related to LVM in a well-studied group of subjects with adrenal incidentaloma. 46 consecutive patients (age 59 ± 9 years) with imaging diagnosis of adrenal incidentaloma and 30 healthy controls underwent echocardiogram for epicardial fat thickness and LVM measurement. Non-functional incidentaloma was confirmed in 40 subjects, whereas 6 patients were actually diagnosed with mild Cushing's syndrome. Epicardial fat thickness was significantly higher in patients with incidentaloma and mild Cushing's syndrome when compared to controls, (p < 0.01 for both). LVM(h2.7) was higher in subjects with adrenal incidentaloma than in controls and higher in subjects with mild Cushing's syndrome than in those with adrenal incidentaloma (p < 0.05 and p < 0.01). Multiple regression analysis showed that epicardial fat thickness was the best correlate (R (2) = 0.36, β 2.8, p < 0.01) of LVM in overall study patients. We showed for the first time that (1) epicardial fat thickness and LVM are higher in subjects with adrenal incidentaloma and (2) epicardial fat thickness independently correlates with LVM. Echocardiographic epicardial fat may serve as non-invasive marker of visceral fat and earlier cardiac abnormalities in patients with adrenal incidentaloma.