Background and Objectives: the cardiovascular adverse events including mortality and heart failure, persist significantly during the first months after the acute phase of ST-segment elevation myocardial infarction (STEMI). The increased level of midregional proadrenomedullin (MR-proADM), at hospital presentation in STEMI patients is considered an independent predictor of short-term and long-term mortality and heart failure. This study aimed to measure MR-proADM levels during the acute and recovery phases of STEMI and corroborate whether MR-proADM level was associated with the adverse cardiac events after recovering from STEMI. Materials and Methods: this prospective study enrolled subjects with acute phase STEMI admitted to the intensive cardiac care unit. After recovering and discharged from hospitalization, subjects were followed-up for 90 days. For MR-proADM measurement, the blood samples during acute phase were withdrawn on hospital admission (MR-proADM-0) and during recovery at the day-30 follow up (MR-proADM-30). Adverse cardiac events were evaluated at 30-day and 90-day follow up, namely a composite of death, chronic heart failure, and hospital readmission of any cardiac causes. Results: 83 subjects were enrolled. The median MR-proADM-0 was 3313.33 pg/mL and MR-proADM-30 was significantly reduced at 292.50 pg/mL, p < 0.001. Nineteen subjects (22.9%) experienced adverse cardiac events at 30-day follow up. The MR-proADM-0 level was independently associated with 30-day adverse cardiac events (adjustedOR 1.002, 95%CI: 1.001–1.003, p = 0.040), after adjustment with other variables. In this case, 25 subjects (32.5%) experienced adverse cardiac events at 90-day follow-up. The MR-proADM-0 level was independently associated with 90-day adverse cardiac events (adjustedOR 1.002, 95%CI: 1.001–1.003, p = 0.049). The higher changes of MR-proADM-0 to MR-proADM-30 also associated with adverse cardiac events at 90 days. Conclusions: The MR-proADM was significantly increased during the acute phase of STEMI and declined during recovery phase. The higher MR-proADM level during the acute phase of STEMI and its change intensity were predictors of adverse cardiac events within the 90-day follow up.