A limited number of studies comparing the main risk scores (RS) for acute coronary syndromes (ACS) have been conducted and there is a limited number of long-term observations of unselected patient cohorts evaluated with the various RS. The aim of this study was to validate 5 RS (TIMI STEMI RS, TIMI NSTEMI/UA RS, GRACE RS, SIMPLE RS and ZWOLLE RS) in a Polish population and to develop a new RS that would specifically predict 1-year mortality in the unselected ACS patient cohort. Single-center ACS registry analysis with 1-year follow-up of 931 patients and prospective comparison of 5 RS was conducted. Creation of an RS was attempted. Risk factors were evaluated in a multivariate logistic regression model. The predictive value of the model was assessed with evaluation of the area under curve (AUC) in receiver-operating characteristic analysis. Twelve independent factors influencing 1-year mortality were identified and of them, clerking, physical findings on admission, first ECG and myocardial necrosis markers demonstrated sufficiently high predictive value. All 5 RS were successfully validated in the target registry and although they all displayed high predictive value, the TIMI RS STEMI (AUC= 0.84) and GRACE RS (AUC= 0.84) proved superior. The developed Banach score offers both high goodness-of-fit and predictive value and may be used irrespective of ACS type.(Circ J 2011; 75: 167-173)