Quantitative electrocardiographic (ECG) and vectorcardiographic (VCG) analysis was carried out in 113 newly diagnosed, middle-aged, non-insulin-dependent diabetics (61 men, 52 women) and 125 non-diabetic control subjects (56 men, 69 women) in order to explore changes attributable to non-coronary heart disease (diabetic cardiomyopathy) in diabetics. Diabetic men had a prolonged PQ interval and women a more negative P-terminal force and a more leftward frontal QRS axis than their non-diabetic counterparts, but no other significant differences we found between diabetic and non-diabetic subjects in various quantitative ECG and VCG variables when the effect of confounding factors (age, obesity, coronary heart disease, hypertension, drugs) was taken into account. The more negative P-terminal force and left axis deviation in diabetic women could be explained by a concomitant left ventricular hypertrophy among them. Non-insulin-dependent (type 2) diabetes, which is commonly preceded by a long duration of asymptomatic hyperglycaemia, is not associated, early in its clinical course, with major ECG and VCG abnormalities suggestive of diabetic cardiomyopathy.