Therapeutic considerations regarding the treatment of hypertension in patients with diabetes mellitus are reviewed. Good blood pressure control is essential in diabetic patients to prevent morbidity and mortality associated with cardiovascular diseases. Hypertension may also accelerate complications of diabetic microvascular disease, nephropathy, and retinopathy. Diuretics (e.g., thiazides, furosemide, ethacrynic acid, bumetanide) and beta blockers have traditionally been used as initial therapy for most patients with hypertension; however, these agents may not be the best choice for diabetics. Adverse metabolic consequences include alteration of glucose metabolism and plasma lipids. Beta blockers may also blunt the ability of patients to recognize symptoms of hypoglycemia. Both diuretics and beta blockers can cause sexual dysfunction in men. Adrenergic agents and vasodilators are associated with a high prevalence of orthostatic hypotension in diabetic patients. The calcium-channel blockers are considered safe and well tolerated when given at low and moderate doses. The angiotensin-converting-enzyme (ACE) inhibitors are able to slow the progression of diabetic nephropathy by reducing the glomerular hypertension that causes it. For the treatment of mild hypertension in diabetic patients, the drugs of choice should include (in descending order) ACE inhibitors, calcium-channel blockers, diuretics, and beta blockers. Severe or resistant hypertension usually requires treatment with combinations of drugs, including a diuretic. Tailoring therapy to individual complications and close monitoring of the patient are essential for safe, effective treatment of hypertension in the diabetic patient.