Objective: Cardiosurgical operative risk can be assessed using the logistic European system for cardiac operative risk evaluation (EuroSCORE) and the Society of Thoracic Surgeons (STS) score. Factors other than medical diagnoses and laboratory values such as the 'biological age' are not included in these scores. The aim of the study was to evaluate an additional assessment of frailty in routine cardiac surgical practice. Methods: 'The comprehensive assessment of frailty' test was applied to 400 patients >/=74 years who were admitted to our centre between September 2008 and January 2010. For comparison, the STS score and the EuroSCORE were calculated. The primary end point was the correlation of Frailty score to 30-day mortality. A total of 206 female and 194 male patients were included. Results: Median Frailty score was 11 [7,15]. Median of logistic EuroSCORE was 8.5% [5.8%; 13.9%]. Median of STS score was 3.3% [2.1%; 5.1%]. There were low-to-moderate albeit significant correlations of Frailty score with STS score and EuroSCORE (p<0.05). There was also a significant correlation between Frailty score and observed 30-day mortality (p<0.05). Patients received isolated coronary artery bypass grafting (CABG) (n=90), isolated valve surgery (n=128), trans-catheter valve implantation (n=59) or combined procedures (n=123). Conclusions: The comprehensive assessment of frailty is an additional tool to evaluate elderly patients adequately before cardiac surgical interventions. The Frailty score combines characteristics of the Fried criteria , of patient phenotype, of his physical performance and laboratory results. Further analysis on a larger patient population is warranted. A combination of the new Frailty score and the traditional scoring systems may facilitate a more accurate risk scoring in elderly high-risk patients scheduled for conventional cardiac surgery or trans-catheter aortic valve replacement.