Early screening for hypertension in diabetic patients and for glycoregulation abnormalities in hypertensives is justified by the additive cardiovascular risks when hypertension and diabetes co-exist and by the accelerated development of diabetic nephropathy and retinopathy if hypertension co-exists. In insulin-dependent diabetes, hypertension is generally preceded by microalbuminuria, known to be reduced by angiotensin converting enzyme inhibitors. The requirement for nephropathy prevention and the hemodynamic and/or tissular effects of this therapeutic class could justify their use at a blood pressure level less than that conventionally considered hypertensive. This strategy must be confirmed by prospective trials, already underway, evaluating the nephroprotective efficacy of this therapy. In non-insulin-dependent diabetes, hypertension is often present before the diabetes is diagnosed and antihypertensive therapy, especially thiazide diuretics, could play a demasking or favorizing role. The optimal blood pressure level to which these patients at high renal and coronary risk should be lowered still has to be determined. A prospective study, comparing the effects of strict (treated diastolic blood pressure less than 80 mmHg) and less strict (treated diastolic blood pressure between 90 and 100 mmHg) hypertensive control on coronary event prevention in essential hypertension, is in progress and will have important implications for hypertension treatment in diabetics. Appropriate treatment of other risk factors, such as hyperlipidaemia and smoking, contributes to coronary and renal prevention in all diabetic hypertensives.