Objective: To explore differences in the health-related quality of life (HRQOL) of patients before and after cardiac surgery, to compare the results with norms of Croatian population and to correlate the results with values of EuroSCORE. Methods: This was a prospective observational study with repeated measurements using the Short Form SF-36 health survey before surgery and 1 year after discharge, to assess changes in quality of life. Results: A total number of 111 patients were included in the study. Seventy-one patients (64%) responded to second measurement of HRQOL 1 year after surgery. The mean age was 61 years, patients were predominantly male and the majority of patients were admitted for coronary artery bypass graft. The prevalence of comorbidity was relatively high. Preoperative mean values of study population were statistically lower than those representing Croatian general population in five out of eight health domains: physical functioning ( p < 0.001), role physical ( p < 0.001), bodily pain ( p < 0.001), social functioning ( p < 0.001) and mental health ( p < 0.001). Data show significant improvement 1 year after discharge in four out of eight health domains: physical functioning ( p = 0.02), role physical ( p < 0.001), social functioning ( p = 0.004) and mental health ( p = 0.03). A subgroup of 30 patients with EuroSCORE !6 shows postdischarge improvements in the majority of scales: role physical ( p < 0.001), bodily pain ( p < 0.001), vitality ( p = 0.03), social functioning ( p = 0.01), role emotional ( p = 0.03) and mental health ( p = 0.002), and group with EuroSCORE <6 shows postdischarge improvement only in one health domain -role physical ( p < 0.001). Conclusions: The health status of patients one year after hospital discharge shows a statistically significant improvement in half of the domains of physical and mental health compared with presurgery status. The high-risk group of patients (EuroSCORE !6) were likely to have significant improvement in greater number of health domains following surgery than the low-and medium-risk group (EuroSCORE <6). #