OBJECTIVE: To study whether prospective measurements of circulating concentrations of brain natriuretic peptide (BNP) could predict mortality in the general elderly population. DESIGN AND SETTING: Circulating BNP was measured in a cohort of 85 year olds from the general population who were followed up prospectively for five years as part of a longitudinal population study, "70 year old people in Gothenburg, Sweden". PATIENTS: 541 subjects from the 85 year old population in Gothenburg. All subjects were investigated for the presence or absence of cardiovascular disorder such as congestive heart failure, ischaemic heart disease, hypertension, and atrial fibrillation. Venous plasma samples were obtained for BNP analysis. MAIN OUTCOME MEASURE: Overall mortality during the prospective follow up period. RESULTS: Circulating concentrations of BNP predicted five-year mortality in the total population (P < 0.001). In subjects with a known cardiovascular disorder, five-year mortality was correlated with increased BNP concentrations (P < 0.01). Increased BNP concentrations predicted five-year mortality in subjects without a defined cardiovascular disorder (P < 0.05). CONCLUSIONS: In an elderly population, measurements of BNP may add valuable prognostic information and may be used to predict mortality in the total population as well as in patients with known cardiovascular disorders. In subjects without any known cardiovascular disorder, BNP was a strong and independent predictor of total mortality.