BACKGROUND: Despite effective treatment with anticoagulants, 2% to 7% of patients with pulmonary embolism will die as a result of their disease. METHODS AND RESULTS: We examined in 110 consecutive patients with pulmonary embolism whether plasma brain natriuretic peptide (BNP), a novel marker of (right) ventricular dysfunction, is a predictor of fatal pulmonary embolism. The relationship between BNP concentration measured at presentation and clinical outcome was assessed by comparing the proportion of outcome events among tertiles. Positive and negative predictive values of BNP levels in the highest and lowest tertiles were calculated. The risk of death related to pulmonary embolism if the BNP level is >21.7 pmol/L is 17% (95% CI, 6% to 33%). The negative predictive value for uneventful outcome of a BNP value <21.7 pmol/L is 99% (95% CI, 93% to 100%). CONCLUSIONS: This is the first study to show that plasma BNP levels seem to predict adverse outcome in patients with acute pulmonary embolism.