The benefits of treating hypertension have been documented by several long-term studies that have shown a decreased incidence of morbidity and mortality associated with stroke, left ventricular failure, and renal insufficiency. With the large number of antihypertensive drugs currently available, several safety factors need to be considered when initially choosing a regimen so as not to adversely influence the potential benefits of blood pressure control. Antihypertensive agents should be chosen based on their hemodynamic profile, the absence of adverse metabolic effects and subjective side effects, and the presence of beneficial effects on the patients' quality of life. Thiazide diuretics and beta-blocking agents have often been recommended as initial therapy in patients with mild to moderate hypertension. However, thiazide diuretics may be less desirable in certain patients because of their effects on lipids, potassium, and glucose tolerance; beta-blocking agents are not ideal for some patients because of their effects on lipids, exercise tolerance, and overall quality of life. The angiotensin-converting enzyme inhibitors, selective alpha 1-blocking agents, and calcium channel blocking agents may be more appropriate for initial therapy of hypertension in many patients.