['B-type natriuretic peptide (BNP) is a marker for heart failure (HF) severity, but its association with hospital readmission is not well defined.', 'We identified all hospital discharges (n=109 875) with a primary diagnosis of HF in the Veterans Affairs Health Care System from 2006 to 2009. We examined the association between admission (n=53 585), discharge (n=24 326), and change in BNP (n=7187) and 30-day readmission for HF or other causes. Thirty-day HF readmission was associated with elevated admission BNP, elevated discharge BNP, and smaller percent change in BNP from admission to discharge. Patients with a discharge BNP ≥ 1000 ng/L had an unadjusted 30-day HF readmission rate over 3 times as high as patients whose discharge BNP was ≤ 200 ng/L (15% vs. 4.1%). BNP improved discrimination and risk classification for 30-day HF readmission when added to a base clinical model, with discharge BNP having the greatest effect (C-statistic, 0.639 to 0.664 [P<0.0001]; net reclassification improvement, 9% [P<0.0001]). In contrast, 30-day readmission for non-HF causes was not associated with BNP levels during index HF hospitalization.'] Does b-type natriuretic peptide predict 30-day readmission for heart failure but not readmission for other causes?