Randomized controlled clinical trials as well as large community-based trials have succeeded in identifying more than 50 biochemical, hemodynamic, functional, demographic, and electrophysiologic factors that may be predictive of life expectancy in patients with heart failure. Of all neurohormonal markers, cardiac norepinephrine spillover may be the strongest predictor of outcome, although measurements of plasma norepinephrine, which is a useful surrogate marker of systemic adrenergic activity, are more widely available. Brain natriuretic peptide also appears to be a strong multivariate indicator of prognosis, although its relative importance requires confirmation. Although left ventricular ejection fraction (LVEF) is a strong predictor of outcome within a large range of LVEF values in patients with moderate heart failure, it loses predictive value in patients with more advanced disease and low LVEF. The cardiothoracic ratio appears to offer independent prognostic information above and beyond LVEF. A variety of studies have revealed metabolic exercise performance, as reflected by peak oxygen consumption, to be a strong predictor of outcome in patients with moderate as well as severe heart failure. Of all demographic variables, advanced age is the most powerful prognostic indicator. The presence of symptomatic ventricular arrhythmias is an important predictor of mortality in patients with heart failure. Medical and surgical interventions that have been proven to prolong survival in patients with heart failure include angiotensin-converting enzyme inhibitors, b-adrenergic blockers, spironolactone (in advanced heart failure), statins (in patients with elevated cholesterol levels), automatic implantable cardioverter defibrillators (in patients with symptomatic ventricular arrhythmias), and cardiac transplantation. Adjunctive angiotensin receptor blockers may also be of significant benefit in reducing mortality, although this is unproven. In everyday clinical practice, a careful history and physical examination, together with measurement of LVEF, should yield the most valuable prognostic information. The prognosis of patients with mild to moderate heart failure is constantly changing, thanks to advances in medical therapy and devices that have improved the outcome for these patients. Despite such progress, however, chronic heart failure (CHF) continues to be associated with a high mortality. Randomized trials as well as community-based studies have identified prognostic factors that may help to identify those patients who are at greatest risk of dying. Because no single study has analyzed all of the proposed risk factors simultaneously, it is not yet possible to rank them in strict order of importance. Nevertheless, this review will examine a variety of biochemical, hemodynamic, functional, electrophysiologic, and demographic risk factors and assess their relative value for predicting the outcome in patients with heart failure.