The usefulness of repeated measures of B-type natriuretic peptide (BNP) in elderly subjects with decompensated heart failure to improve risk stratification remains poorly known. This prospective cohort study included 61 consecutive patients older than 70 years (mean age, 82.7 years) hospitalized for decompensated heart failure. Clinical, radiologic, biologic, and echographic data were collected at admission and at discharge. The median BNP level at admission was 1136 pg/mL and the mean change during the hospitalization was -32%. Cardiac death or readmission were best predicted by the change in BNP levels, with the poorest prognosis in patients who did not achieve a decrease of at least 40% (hazard ratio, 4.03; 95% confidence interval, 1.50-10.84 in multivariate analysis). Admission of an elderly patient for decompensated heart failure is a daily situation in clinical practice, in which 2 BNP measurements seem to provide reliable information on long-term prognosis.