Objectives: Brain natriuretic peptide (BNP) levels correlate with prognosis in patients with cardiac disease and may be useful in the risk stratification of cardiac patients undergoing noncardiac surgery (NCS). The objective of this study was to examine whether BNP levels predict perioperative events in cardiac patients undergoing NCS. Methods: Patients undergoing NCS with at least 1 of the following criteria were included: a clinical history of congestive heart failure (CHF), ejection fraction <40%, or severe aortic stenosis. All patients underwent echocardiography and measurement of BNP performed using the ADVIA-Centaur BNP assay (Bayer HealthCare). Clinical endpoints were death, myocardial infarction or pulmonary congestion requiring intravenous diuretics at 30 days of follow-up. Results: Forty-four patients were entered into the study; 15 patients (34%) developed cardiac postoperative complications. The mean BNP level was 1,366 ± 1,420 pg/ml in patients with events and 167 ± 194 pg/ml in patients without events, indicating a highly significant difference (p < 0.001). The ROC area under the curve was 0.91 (95% CI 0.83–0.99) with an optimal cutoff of >165 pg/ml (100% sensitivity, 70% specificity). Conclusions: BNP levels may predict perioperative complications in cardiac patients undergoing NCS, and the measurement of BNP should be considered to assess the preoperative cardiac risk.