Background: Pentraxin-3 (PTX3) was a useful marker for localized vascular inflammation and damage in the cardiovascular system. Recent studies have shown that plasma PTX3 is elevated in patients with myocardial infarction; however, its prognostic value still remains unclear. Aims: This study aimed to investigate the relationship between PTX3 and in-hospital and three months of a major adverse cardiac event (MACE) in acute ST-elevation and non-ST-elevation myocardial infarction patients. Methods: This cohort study conducted from September 1st, 2018 to October 31st, 2019 in Dr. Moewardi Hospital. A 144 patient were observed during hospitalization and 130 survived patient were follow up for three months. The admission PTX3 was compared between the patient with and without MACE. Higher levels of PTX3 were defined as concentrations greater than the optimal cut-off value derived from the Receiver Operating Characteristic (ROC) curve. Results: Among patients, 43.75% was anterior STEMI, 35.42% was inferior STEMI, and 20.38% was NSTEMI with median PTX3 level was 8.16 (0.21-69.35) ng/mL. The in-hospital MACE occurred in 52% of patients, while three months of MACE occurred in 17% patient. Patients with MACE had a higher level of PTX3 compared without MACE (p<0.001) during hospitalization, but not in three months follow up (p=0.408). Multivariate analysis also shown PTX3 was as a predictor of in-hospital MACE (OR 1.127; p=0.001), along with heart rate (OR 1.025; p=0.015). There are different of in-hospital MACE between the patient with high (≥8.247 ng/mL) and low (<8.225 ng/mL) PTX3 level with a hazard ratio (HR) 2.142 (95%CI 1.315-3.487; p=0.002), but the result did not similar after three months follow up (p=0.373). Conclusion: The PTX3 can be used as a predictor of in-hospital MACE but not for three months follow up.