Beta-blockers are an important cardiovascular drug class, recommended as first-line treatment of numerous diseases such as heart failure, hypertension, and angina, as well as treatment after myocardial infarction. However, responses to a beta-blocker are variable among patients. Results of numerous studies now suggest that genetic polymorphisms may contribute to variability in responses to beta-blockers. This review summarizes the pharmacogenetic data for beta-blockers in patients with various diseases and discusses the potential implications of beta-blocker pharmacogenetics in clinical practice.