Within the last five years, assay systems for measurement of plasma levels of brain natriuretic peptide (BNP) have been approved as a diagnostic aid for heart failure (HF). Similarly, nesiritide, a recombinant form of human BNP, has been approved for the treatment of acutely decompensated HF. Both BNP as a diagnostic test and a therapeutic modality are rapidly becoming integrated into clinical practice. The purpose of this review is to provide a brief overview of the physiology of the natriuretic peptides relevant to their informed clinical use. The current literature regarding the utility of measuring BNP for the diagnosis and management of HF is reviewed and practical recommendations regarding the interpretation of BNP levels are offered. The clinical literature regarding the use of recombinant BNP for the treatment of HF is reviewed, underscoring current gaps in our knowledge regarding the indications for and benefits of this novel agent.