Sixty-one children with insulin-dependent diabetes mellitus and twenty-three healthy subjects were investigated. The patients with diabetes mellitus aged 4 to 20 years (13.4 +/- 4.0) had had diabetes for 1 to 16 years (6.4 +/- 3.5). There were no cardiovascular risk factor other than diabetes. Patients received no medication other than insulin. The following echocardiographic and Doppler parameters of the left ventricle were analyzed in both groups: systolic and diastolic dimensions, systolic time intervals, fractional shortening, mean velocity of circumferential fiber shortening, percent relaxation of the left ventricular posterior wall at 50% of diastole, peak velocity of early (E) and late atrial (A) mitral flow. E/A ratio, deceleration of the E-wave, and the isovolumetric relaxation time. None of the parameters were significantly different between the groups. There was no relation observed between duration of diabetes and any of the parameters analyzed. It is concluded that there is not echocardiographic data to support the concept of diabetic cardiomyopathy in adolescents with type I (insulin-dependent) diabetes mellitus.