Acute decompensated heart failure (ADHF) has emerged as a major healthcare problem. It causes approximately 3% of all hospitalizations in the United States, with the direct medical cost of these hospitalizations estimated at $18.8 billion per year. Early recognition, risk stratification, and evidence-based treatment are crucial in reducing the morbidity, mortality, and costs associated with this disorder. Classic signs and symptoms of ADHF, such as rales, dyspnea, and peripheral edema, may be absent at hospital presentation and, even when present, are not specific to this disorder. As a result, serum B-type natriuretic peptide level is now used to rapidly and accurately detect ADHF. Multivariate analyses have identified renal dysfunction, hypotension, advanced age, hyponatremia, and comorbidities as significant and independent mortality risk factors. Based on these factors, mortality risk can be stratified from very low to very high using published algorithms that have been validated in independent populations. Evidence-based guidelines for the treatment of ADHF are available from both the European Society of Cardiology and the Heart Failure Society of America. In general, an intravenous loop diuretic, either alone or in combination with a vasodilator, is recommended as initial therapy in patients with volume overload, depending on the patient's clinical status. Use of inotropic agents should be limited to the small subset of patients with low-output syndrome and significant hypotension. In any event, frequent monitoring of clinical response is essential, with subsequent therapy determined by this response. Finally, focused patient education during hospitalization may help reduce readmissions for ADHF.