Natriuretic peptide hormones, a family of vasoactive peptides with many favourable physiological properties, have emerged as important candidates for development of diagnostic tools and therapeutic agents in cardiovascular disease. The rapid incorporation into clinical practice of bioassays to measure natriuretic peptide concentrations, and drugs that augment the biological actions of this system, show the potential for translational research to improve patient care. Here, we focus on the physiology of the natriuretic peptide system, measurement of circulating concentrations of B-type natriuretic peptide (BNP) and the N-terminal fragment of its prohormone (N-terminal BNP) to diagnose heart failure and left ventricular dysfunction, measurement of BNP and N-terminal BNP to assess prognosis in patients with cardiac abnormalities, and use of recombinant human BNP (nesiritide) and vasopeptidase inhibitors to treat heart failure.