Practice guidelines recommend that post myocardial infarction (MI) patients should be started and continued indefinitely on oral beta-blocker therapy unless absolutely contraindicated or not tolerated. Patients with post-MI left ventricular dysfunction (LVD) are at particularly high risk for recurrent cardiovascular events, heart failure, sudden death, and mortality and have been shown to derive substantial benefit from certain beta-blockers. Nevertheless, many of these patients are not prescribed beta-blockers, and some patients are treated with agents whose long-term use has not been shown to be effective. This article discusses the clinical trial evidence supporting the use of beta-blockers in patients post MI with LVD, provides the rationale for choosing specific beta-blockers, and presents practical approaches to implement this evidence-based therapy in the acute and chronic post-MI period.