Background: For the Asian patients with STEMI undergoing PCI, ACEIs are known to have a better outcome than ARBs. However, there is limited evidence to suggest so. Methods: Among the STEMI registry consist of 1142 Korean patients, we compared the MACE, the composite of myocardial infarction, stoke, death, admission for heart failure, and target vessel revascularization, between the ACEI and ARB groups (Set 1). Further, we defined adequate medication as the administration of a dose equal to or higher than the initiation dose of ACEI according to the heart failure guideline recommendation with a mandatory addition of beta-blockers, and compared the outcomes between the inadequate and adequate medication groups (Set 2). Propensity score matching was used to eliminate difference. Results: In the Set 1 comparison, patients in the ACEI group had a better outcome than those in the ARB group for both whole and matched populations (whole and matched population: Cox regression hazard ratio [HR], 0.645 and 0.535; 95% confidence interval [CI], 0.440–0.944 and 0.296–0.967; p = 0.024 and p = 0.039, respectively). In the Set 2 comparison for the whole population, patients in the inadequate medication group had more MACE than those in the adequate medication group (HR, 0.673; 95% CI, 0.459–0.985; p = 0.042). However, no difference was observed after propensity score matching (HR, 1.023; 95% CI, 0.654–1.602; p = 0.919). Conclusion: ACEIs might be a better choice than ARBs after primary revascularization. However, this study’s findings suggest that early ACEI dose escalation combined with beta-blocker use may not improve prognosis.