Objectives: The aim of this study was to determine the role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the prognostication of patients ≥80 years of age undergoing percutaneous coronary intervention (PCI).Background: Elderly patients with coronary artery disease in need of PCI represent a growing patient population. Advanced risk prediction in this frail and comorbid patient population is important.Methods: A total of 460 consecutive patients ≥80 years of age undergoing PCI for acute (ACS) or chronic coronary syndromes (CCS) at the University Hospital Zurich, Switzerland, between January 2016 and December 2018 and with available baseline NT-proBNP levels were included in the analysis. Patients were stratified according to baseline NT-proBNP levels. The primary endpoint was all-cause mortality at a median follow-up of 33 (interquartile range: 3-392) days.Results: Median baseline NT-proBNP levels were 1411 (457-3984) ng/L. All-cause mortality was 7.8% in the lowest and 27.8% in the highest NT-proBNP quartile group (p < 0.001). In patients with ACS, all-cause mortality was 4.8% and 30.4% in the lowest and the highest NT-proBNP quartile (p < 0.001), and corresponding rates in patients with CCS were 11.1% and 22.2% (p = 0.38). In multivariable Cox regression analysis, baseline NT-proBNP levels were independently associated with an increased risk of all-cause mortality (adjusted hazard ratio: 1.00, 95% confidence interval: 1.00-1.00, p = 0.04).Conclusions: Baseline NT-proBNP levels were identified as independent predictor of mortality in elderly (≥80 years) patients undergoing PCI. Hence, baseline NT-proBNP allows for the identification of a high-risk elderly patient subset.