The treatment of hypertension in patients with diabetes, obstructive airway disease, impaired renal function, or congestive heart failure (CHF) is discussed. Specifically, the value of alpha 1-adrenoceptor blocking agents in such patients is reviewed. An individualized approach to therapy is required, with careful consideration of the effects of different drugs on the existing metabolic and hemodynamic situation. In diabetic individuals, commonly used step-1 agents may impair glucose tolerance; beta-adrenergic blockade may increase blood glucose levels and significantly change response to insulin-induced hypoglycemia. Diabetic patients may also be especially sensitive to side effects of some centrally acting antihypertensive agents. In patients with obstructive airway disease, beta-blockade and alpha-stimulation worsen bronchospasm; although beta-stimulants produce bronchodilatation, they often are contraindicated in hypertensive patients due to their stimulatory effects on the heart. In patients with impaired renal function, therapy for hypertension may include problems such as an increased half-life of antihypertensive agents and retention of active metabolites. In patients with CHF, if blood pressure is not normalized with diuretics, more aggressive therapy may be required. According to results of several studies discussed, the alpha 1-adrenoceptor blocking-agent prazosin appears to be a safe and effective therapy, causing a minimum of side effects, for treatment of hypertension in patients with these conditions.