This study sought to determine plasma levels of B-natriuretic peptide (BNP) in patients with light-chain-associated amyloidosis and correlate them with the presence or absence of heart failure (HF) and the presence or absence of echocardiographic abnormalities. Patients with normal echocardiographic results had significantly lower BNP levels than those with echocardiographic features of cardiac amyloidosis, whereas BNP levels in the group with HF did not differ from those in patients with asymptomatic cardiac amyloidosis. This observation supports previous observations, suggesting that the elevation of BNP in cardiac amyloidosis may be due not only to elevated ventricular filling pressure but also to direct myocyte damage due to extracellular deposits of amyloid.