The aim of the present study was to assess structural characteristics of the left ventricle by echocardiography in a group of patients with Cushing's syndrome compared with a control population. Eighteen patients with Cushing's syndrome and 18 controls, matched for sex, age, body weight, body surface area, blood pressure (BP) and duration of hypertension were investigated by M-mode (2-D derived) echocardiography. In each of the two groups, 11 of 18 subjects were hypertensive. Relative wall thickness (RWT) was above normal (> 0.45) in 11 (five normotensive and six hypertensive) of 18 patients with Cushing's syndrome and in two (hypertensive) of 18 controls. Left ventricular mass index was abnormal in three (one normotensive and two hypertensive) patients with Cushing's syndrome and in four hypertensive controls. All other systolic function indices were within normal and similar in both groups. No correlation was found between RWT and BP as well as between RWT and urinary cortisol levels in patients with Cushing's syndrome. A significant correlation was found between RWT and duration of disease. Echocardiography after successful surgery showed normalisation of RWT in five of six patients in whom it was previously abnormal. Our data suggest that time factor, i.e. long-lasting exposure to increased cortisol, rather than hormone or BP levels is the most relevant determinant of left ventricular concentric remodeling in patients with Cushing's syndrome.