An abundance of clinical trial data indicates that lipid-regulating therapy reduces coronary artery disease morbidity and mortality. In patients with established coronary artery disease, lipid regulation has been shown to attenuate progression of atherosclerosis and extend survival. In primary prevention, a clear benefit of therapy on survival has not been demonstrated, leading some to question its value. However, the probability of false negatives for total mortality in primary-prevention trials is high, and the potential benefit of primary-prevention measures to public health is great. Additional investigations should further clarify the role of lipid-regulating therapy, particularly in important populations for whom fewer data are available, such as women and the elderly.