Background : Prediction of postoperative cardiac complication is important in the medical management of patients undergoing noncardiac surgery. The purpose of this study was to assess NT-proBNP as a prognostic factor for prediction of postoperative cardiac risk (PCR) compared with existing cardiac indices in elderly patient undergoing orthopedic surgery. Method : From September 2003 to January 2004, we examined 50 patients who are older than 60 years, to be scheduled to undergo orthopedic surgery. Plasma NT-proBNP concentration, clinical cardiac indices, left ventricular ejection fraction were measured at the before operation. The postoperative outcomes and predictors of PCR were identified. Results : Cardiac complication occurred in 22% of patients. Statistically significant increase in cardiac complication was observed in patients with higher concentration of plasma NT-proBNP (p<0.001), higher original cardiac index score (p<0.001), higher revised cardiac index score (p=0.004), major group of American college of cardiology/American heart association guideline (p=0.018). NT-proBNP concentrations was positively correlated with original cardiac index score (r=0.666, p<0.001), revised cardiac index score (r=0.429, p=0.002), and grouping of ACC/AHA guideline (r=0.497, p<0.001). The area under the receiver-operating characteristic curve for plasma NT-proBNP (0.946, 95% CI) was superior as compared with other cardiac indices. The optimal cut-off point for prediction of PCR occurred at a plasma concentration of 539.3 pg/mL for NT-proBNP, provided 90.9% sensitivity, 92.3% sensitivity, 79.9% positive predictive value, and 97.3% negative predictive valvue. The independent predictors for postoperative adverse cardiac event were age and Goldman index (p=0.025, 0.020, respectively). Conclusion : Plasma NT-proBNP level was useful parameter for prediction of postoperative cardiac complication.