Our understanding of factors contributing to the progression of heart failure has advanced dramatically over the past 2 decades. We have also gained considerable insight into the pharmacology of beta-adrenergic receptor blockers (beta-blockers). Based on this knowledge, we can now appreciate the potential of these drugs for the treatment of heart failure. Several beta-blockers have been shown to be clinically effective in the treatment of heart failure. Critical evaluation of the evidence from basic research studies, as well as clinical trials in patients with heart failure, helps to delineate the theoretical and clinical benefits of beta-blockers.