Objectives: The aim of this paper is to examine whether there is a correlation between intraoperative risk factors and fatal outcome in cardiac surgery patients. Study design: A cross-sectional study with historical data Participants and methods: The study included patients operated on at the Department of Cardiac Surgery of the University Hospital Center Osijek from October 2007 to October 2019. The patients were divided into two groups. The first group included patients with positive outcome of the operation. The second group included patients with fatal outcome, which occurred during or after the surgery, but before being discharge from the ward. Results: Out of the total of 3646 patients, 77,48% were men and 22,52% women. The median age of survivors is 66 and the median age of patients with fatal outcome is 68. The median value of EuroSCORE is 3 in patients who survived the surgery and 7 in patients with fatal outcome. There is also a significant difference between the groups in patients who underwent reoperation and in patients whose surgery was urgent. The number of administered blood units is significantly higher in deceased patients. Significantly more deceased patients used some form of mechanical support. Deceased patients spent significantly more time on extracorporeal circulation machine. The duration of the aortic cross-clamp is also significantly longer in the group of deceased patients. Conclusion: EuroSCORE value and gender (female) are factors associated with fatal outcome. Intraoperative factors affecting the outcome of the surgery include: the administered amount of blood units, the use of mechanical support, the duration of the ECC and the aortic cross-clamp.