The existence of a distinct diabetic cardiomyopathy, characterized by a raised left ventricular mass, has previously been suggested. However, as diabetes mellitus is associated with both left ventricular hypertrophy and hypertension a confounding effect of raised blood pressure in diabetic patients has to be considered. In the present cross-sectional study an echocardiographical examination was performed as part of a health screening survey in 582 males, aged 70 years. After the exclusion of subjects with coronary heart disease or those on regular antihypertensive treatment, 30 normotensive subjects with diabetes were compared with 10 subjects with non-insulin-dependent diabetes (NIDDM) and a diastolic blood pressure 90 mm Hg or more and 203 normotensive control subjects with normal glucose tolerance. Both groups with NIDDM showed a significantly increased left atrial diameter (4.4 +/- 0.7 vs 4.0 +/- 0.5 cm, p < 0.05) and an increased atrial component in diastole (A-wave, p < 0.01) compared to the control subjects. Left ventricular mass was, however, only marginally and not significantly elevated in the diabetic subjects when compared to the healthy control subjects (133 +/- 19 and 133 +/- 28 vs 128 +/- 25 g/m2). Only in the subjects with concomitant diabetes and a raised blood pressure was the intraventricular septum significantly enlarged (p < 0.05). Thus, in the present sample no distinct diabetic cardiomyopathy with an increased left ventricular mass, independent of the influence of hypertension could be detected. The myocardial alterations in these diabetic males were restricted to an increased left atrial size and an impaired diastolic function.