Natriuretic peptides (NP) are released from the heart in response to pressure and volume overload. The biologic properties of NPs include counterregulation of the rennin-angiotensin-aldosterone pathway and a decrease in sympathetic tone resulting in diuresis, natriuresis, and vasodilation. Natriuretic peptides help to maintain fluid balance and blood pressure in a healthy physiologic range. The B-type natriuretic peptide (BNP) and its N-terminal precursor (NTpBNP) have become important diagnostic biomarkers of cardiovascular diseases (CVDs) in adults. Although many studies suggest that BNP also is a reliable test for diagnosing significant CVDs in children, data are lacking on whether additional use of BNP increases diagnostic accuracy and predicts prognosis. This comprehensive review describes the utility of BNP and NTpBNP for various CVDs of the neonatal and pediatric age groups. Because BNP is not a stand-alone test, it should not replace history, physical examination, or clinical judgment, but it has a clear value in adding details to the whole story for children, thus enabling the front-line physicians to make a diagnosis, especially in the acute care setting.