Introduction:Acute coronary syndrome (ACS) is one of the most common health problems in the world and the leading cause of death.Goal:The goals of this study are to determine: ACS type, risk factors, incidence and the seasonal distribution of occurrence Spring/Summer, Autumn/Winter, ACS incidence by age and gender, and complications (post-infarction angina and heart failure) and fatal outcomes of ACS per season.Material and methodology:This study is designed as retrospective-prospective and analytical, which included 250 patients hospitalized in the Intensive Cardiac care unit of the Clinic for heart disease, blood vessels and rheumatism in the period from June 2013 to July 2014. It was assumed that there is the influence of the seasons on the incidence and characteristics of ACS. Material used were the medical records and data from the history of illness.Results:The most common type of ACS was ST elevation myocardial infarction (STEMI), without statistical significant difference between seasons. Presence of risk factors is not significantly different between seasons, with the hypertension as the most common risk factor for ACS during both seasons. The highest incidence of ACS was recorded in December during the winter season, while the lowest incidence was recorded in March. The occurrence of ACS during the Spring/Summer, Autumn/Winter was different according to age, with more frequent occurrence of ACS in older patients during the winter months. ACS complications (postinfaction angina and cardiac insufficiency) were also statistically different between seasons (p=0.048). Fatal ACS is more often recorded during the season Autumn/Winter compared to Spring/Summer season (p=0.001).Conclusion:The results suggest seasonal meteorological impact on the incidence, complications and outcomes of ACS, so there is a necessity that patients adapt their lifestyle and health professionals to improve the ACS treatment.