Objective: To examine the quality of life in patients with heart failure and acute coronary syndrome, who are being treated at the Osijek Clinical Hospital Center, Department of Cardiovascular Diseases. Study design: cross-sectional study Subjects and methods: 180 patients participated in the study. Patients diagnosed with heart failure, coronary heart disease and acute coronary syndrome were included. The research used an anonymous questionnaire consisting of general socio -demographic questions and a physical and mental health assessment questionnaire, SF-36. Results: 111 men and 69 women participated in the research. The median age of the respondents is 68 years. 62 (34.4 %) patients rate their current health as good, and 61 (33.9 %) as mediocre. Comparing a year ago, 82 (45.6%) patients assessed their current state of health as slightly worse than a year ago. The state of health of 106 (60%) patients is severely limited during heavy physical activity , and 89 (49.4%) patients are unable to walk several blocks. Unlike men, women rated physical functioning, limitation due to physical difficulties, general perception of health, vitality and energy, and limitations due to emotional difficulties significantly worse. Older patients have a worse evaluation of the pain domain and the domain of general perception of health. Conclusion: Assessment of the physical and mental domains of health showed a reduced quality of life. Cardiovascular diseases have a number of negative consequences on human health and the functionality of the organism. It is important to assess the quality of life because it is the main outcome of treatment and rehabilitation, in order to implement measures to reduce rehospitalization , mortality and poor quality of life.