Morbidity and mortality in diabetes are caused mainly by its vascular complications, both in the microcirculation and in the large vessels. Diabetic nephropathy and retinopathy are the clinical hallmarks of microangiopathy, which may lead to end-stage renal failure and blindness. The cardiovascular complications in diabetes consist mainly of an accelerated form of atherosclerosis. Systemic hypertension is an early and frequent phenomenon. Nocturnal hypertension is also more frequent in people with diabetes compared with the nondiabetic population. Capillary hypertension has been demonstrated in type 1 diabetic patients. Poor metabolic control may induce elevation in blood pressure, but data are conflicting. The prevalence of white-coat hypertension in the diabetic population is comparable with that in the nondiabetic population. Prospective observational studies in type 1 and type 2 patients have revealed that abnormally increased urinary albumin excretion and other potentially modifiable risk factors--such as hypertension, smoking, poor metabolic control, and social class--predict increased all-cause mortality and cardiovascular mortality. Arterial hypertension is a risk factor in the initiation and progression of diabetic micro- and macroangiopathy. Diabetes, hypertension, and smoking are the three most important risk factors for fatal and nonfatal stroke. A randomized, double-blind, parallel study has revealed that the 5-year major cardiovascular disease rate was lowered by 34% for antihypertensive treatment compared with placebo. Furthermore, the study found a trend for lower all-cause mortality for low-dose antihypertensive-treated diabetic patients. Effective blood pressure reduction with ACE inhibitors and/or non-ACE inhibitors, frequently in combination with diuretics, reduces albuminuria, delays the progression of nephropathy, postpones end-stage renal failure, and improves survival in diabetic nephropathy.