The rationale for beta blockade in heart failure is now well established. Heart failure mortality, which is predicted by neurohormonal activation, remains high despite modern treatment, including angiotensin-converting enzyme (ACE) inhibition, and additional neurohormonal blockade has further therapeutic potential. Previous clinical trial experience in heart failure, most of which has been in patients with idiopathic cardiomyopathy, indicates consistent improvement in ventricular function, although variable changes in symptoms and exercise performance. However, the major burden of heart failure occurs in patients with ischemic heart disease, and in this respect it is notable that beta blockade following myocardial infarction confers a significant mortality benefit in subgroups with heart failure. An overview of all currently available randomized clinical trials of beta blockade in heart failure, which includes more than 1600 patients, indicates a mortality risk reduction of approximately 20%, but with wide confidence intervals. A large scale trial with several thousand patients is required to confirm reliably a plausible 20% mortality reduction with beta blockade in heart failure. The dissociation of clinical and mortality effects demonstrated with other heart failure treatments indicates the necessity for an appropriately powered mortality study that could define a major improvement in heart failure therapy for the future. The response to beta blockade will vary according to heart failure severity. A cautious dosetitration approach is required in all cases. In severe heart failure, symptomatic improvement may result, but for the large group of patients with moderate and stable heart failure, the principal aim of treatment is improved longevity.