Background The increase in soluble suppression of tumorigenicity 2 (sST2) both in the diagnosis and prognosis of heart failure is well established; however, existing data regarding sST2 values as the prognostic marker after myocardial infarction (MI) are limited and have been conflicting. This study aimed to assess the clinical significance of sST2 in predicting 1-year adverse cardiovascular (CV) events in MI patients. Materials and methods In this prospective study, 380 MI patients were included. Participants were grouped into low sST2 (n = 264, mean age: 60.0 ± 12.1 years) and high sST2 groups (n = 116, mean age: 60.5 ± 11.6 years), and all study populations were followed up for major adverse cardiovascular events (MACE) which are composed of CV mortality, target vessel revascularization (TVR), non-fatal reinfarction, stroke and heart failure. Results During a 12-month follow-up, 68 (17.8%) patients had MACE. CV mortality and heart failure were significantly higher in the high sST2 group compared to the low sST2 group (15.5% vs. 4.9%, p = 0.001 and 8.6% vs. 3.4% p = 0.032, respectively). Multivariate Cox regression analysis concluded that high serum sST2 independently predicted 1-year CV mortality [hazard ratio (HR) 2.263, 95% confidence interval (CI) 1.124-4.557, p = 0.022)]. Besides, older age, Killip class >1, left anterior descending (LAD) as the culprit artery and lower systolic blood pressure were the other independent risk factors for 1-year CV mortality. Conclusions High sST2 levels are an important predictor of MACE, including CV mortality and heart failure in a 1-year follow-up period in MI patients.