Objective: The presence of Metabolic syndrome (MetS) promotes the development of atherosclerotic cardiovascular disease as well as the appearance of its complications and is a sole indicator of the elevated risk for new cardiovascular events. The aim of this study is to determine the prevalence and the impact of MetS on the appearance of new unwanted cardiovascular events in patients with STEMI treated with primary percutaneous coronary intervention. Design and method: The study group consisted of 507 consecutive STEMI patients treated with primary percutaneous coronary intervention (pPCI) in Clinical Centre of Serbia. During the 36 month-follow up, a telephone visit was conducted in all patients after 1, 3, 6, 12, 24 and 36 months. All the patient who reported new cardiovascular events were called up for events evaluation. For patients who died during the follow up, hospital records and necrophy data were reviewed. AHA/NHLBI (American Heart Association and national Heart, Lung and Blood Institute) criteria were used for diagnosing the patients. Results: The prevalence of MetS in our study was 42.80% (217 patients). During the three-year follow-up, a significant increase of unwanted cardiovascular events (p = 0.0063) was detected in the group of patients with MetS. The presence of MetS in our patients was associated with relative risk for new myocardial infarctions 3.77 (95% CI (1.45–9.80);p = 0.001) and with relative risk for the occurrence of congestive heart failure 1.43 (95% CI (1.07–2.64);p = 0.027). Among the risk factors for MetS, hyperglycemia solely had to be independently associated with cardiovascular death (OR 3.39 95%CI (1.70–6.77) (p = 0.001)), whereas it did not have a significant influence on the appearance of new myocardial infarctions and congestive heart failure. Elevated blood pressure turned out to be a moderate risk for the appearance of new unwanted cardiovascular events while elevated triglyceride level, low HDL cholesterol and obesity did not significantly influenced the appearance of new cardiovascular events and did not present a significant risk. Conclusions: MetS is significantly associated with new myocardial infarction and the occurrence of heart failure, among patients with STEMI regardless of the fully conducted secondary prevention in these patients.