B-type natriuretic peptide (BNP) is a neurohormone synthesized in the cardiac ventricles. It is released as N-terminal pro-BNP (NT-proBNP) and cleaved enzymatically to the NT fragment and the immunoreactive BNP. Measurement of BNP is now available as a rapid bedside assay that is easily available to physicians in an office, clinic, emergency department, or inpatient setting. It has proven utility in the emergency department diagnosis of congestive heart failure (CHF) in patients with unclear causes of dyspnea. The use of BNP level as a criterion for hospital admission has been studied as has its use as an aid in decision-making regarding the adequacy of treatment and readiness for hospital discharge. Treatment of chronic CHF in outpatients using BNP as a guide for the intensity of pharmacological therapy shows promise in further decreasing the rate of adverse events associated with this diagnosis. Other uses for BNP measurement include the prognostication of CHF exacerbation and myocardial infarction, and screening those at risk to identify patients that may benefit from early intervention and treatment of early CHF.