The prevalence of coronary heart disease, left ventricular failure and hypertension was examined in a representative group of 133 newly diagnosed Type 2 (non-insulin-dependent) diabetic subjects (70 men, 63 women), aged 45 to 64 years, and in a group of 144 randomly selected non-diabetic control subjects (62 men, 82 women) of the same age group. The prevalence of previous myocardial infarction (major Q-QS abnormalities in resting ECG and/or myocardial infarction verified at hospital) was increased 1.7-fold in male (NS) and 4.4-fold in female (p = 0.007) diabetic patients compared with that found in non-diabetic subjects. Chest pain symptoms and ischaemic ECG abnormalities were about twice as common among diabetic than among non-diabetic subjects. The frequency of coronary heart disease defined by chest pain symptoms and ECG abnormalities was 3.5 times higher in male (p = 0.001) and 3.1 times higher in female (p = 0.001) diabetic patients than in the respective non-diabetic subjects. The frequency of current digitalis therapy was increased 3.3-fold in male (p = 0.006) and 3.9-fold in female (p = 0.001) diabetic patients suggesting an increased frequency of left ventricular failure among diabetic subjects. The prevalence of hypertension, based on the elevated blood pressure levels and/or current use of antihypertensive drugs, was increased 1.6-1.7-fold among the diabetic patients.