Sixty patients with non-insulin-dependent diabetes underwent M-mode echocardiographic examination. They were all in good metabolic control under treatment with oral antidiabetic drugs and/or diet; none had clinical evidence of micro- or macroangiopathy, cardiovascular disease, arterial hypertension, or other associated risk factors. The control group consisted of 30 normal subjects. No significant differences were shown either with routine or computer-assisted evaluation of the echocardiograms; if there was a significant difference, there was a wide overlap with normal values. However, alterations of the systolic function of the left ventricle were shown by the reduction of the percentage fractional shortening during the first third of systole (9.14 +/- 5.85 vs 12.27 +/- 7.04, p less than 0.05); alterations of the diastolic function were shown by the marked mitral opening delay (54.15 +/- 20.64 msec vs 10.57 +/- 5.18, p less than 0.00001) and the presence of a B notch (50% of the diabetics). In particular, the B notch seemed to be associated with more severe impairment of left ventricular performance. Therefore, these data appear particularly useful in detecting even slight abnormalities in cardiac function in diabetic patients.