Purpose: The frailty concept has become a fundamental part of daily clinical practice. In this study our purpose was to create a risk estimation method with a comprehensive aspect of patients' preoperative frailty. Patients and methods: In our prospective, observational study, patients were enrolled between September 2014 and August 2017 in the Department of Cardiac Surgery and Department of Vascular Surgery at Semmelweis University, Budapest, Hungary. A comprehensive frailty score was built from four main domains: biological, functional-nutritional, cognitive-psychological and sociological. Each domain contained numerous indicators. In addition, the EUROSCORE for cardiac patients and the Vascular POSSUM for vascular patients were calculated and adjusted for mortality. Results: Data from 228 participants were included for statistical analysis. A total of 161 patients underwent vascular surgery, and 67 underwent cardiac surgery. The preoperatively estimated mortality was not significantly different (median: 2.700, IQR (interquartile range): 2.000-4.900 vs. 3.000, IQR: 1.1406.000, P 5 0.266). The comprehensive frailty index was significantly different (0.400 (0.358-0.467) vs. 0.348 (0.303-0.460), P 5 0.001). In deceased patients had elevated comprehensive frailty index (0.371 (0.316-0.445) vs. 0.423 (0.365-0.500), P < 0.001). In the multivariate Cox model an increased risk for mortality in quartiles 2, 3 and 4 compared with quartile 1 as a reference was found (AHR (95% CI): 1.974 (0.982-3.969), 2.306 (1.155-4.603), and 3.058 (1.556-6.010), respectively). Conclusion: The comprehensive frailty index developed in this study could be an important predictor of long-term mortality after vascular or cardiac surgery. Accurate frailty estimation could make the traditional risk scoring systems more accurate and reliable.  Kulcsszavak: frailty, frailty assessment, frailty score, preoperative risk, risk stratification, vascular surgery, cardiac surgery