Metabolic syndrome (MetS) is occurrence of diabetes mellitus/glucose intolerance and at least two of the following: arterial hypertension, central obesity, dyslipidemia and/or microalbuminuria (WHO). Aim of the study was to compare the size of myocardial infarction, heart failure occurrence and rate of hospital mortality in both sexes and according to MetS. Group of patients with MetS had larger myocardial infarction size expressed by "peak-CK" (p=0.003) and "peak-MB-CK" values (p=0.002). While in patients without MetS myocardial infarction size was larger in males, in MetS group myocardial infarction size was larger in females. Heart failure was also more often in MetS group, as well as rate of previous myocardial infarction and hospital mortality. Conclusively, we can say that group of patients with MetS, especially females having ACS are proned to have more extensive myocardial infarction, to have heart failure, had more often previous infarction and have higher hospital mortality.