OBJECTIVE Patients aged ≥75 years compose a high-risk subgroup for acute myocardial infarction (AMI). It is unknown whether myocardial perfusion in these patients is decreased compared with younger ones after primary percutaneous coronary intervention (PPCI), which may contribute to their worse prognosis. We compared epicardial and myocardial perfusions as well as short-term outcomes between elderly and younger patients undergoing PPCI. METHODS A total of 547 consecutive PPCI patients were prospectively enrolled; of these, 106 were elderly (≥75 yrs). Epicardial perfusion was evaluated by the Thrombolysis in Myocardial Infarction (TIMI) flow grade and corrected TIMI frame count (CTFC), and myocardial perfusion was evaluated by the TIMI myocardial perfusion grade (TMPG) and ST-segment resolution (STR). RESULTS Despite comparable epicardial perfusion pre- and post-PPCI, elderly patients had impaired myocardial perfusion after PPCI, as measured by reduced TMPG (35.9% vs 14.5%, p=0.001) and absent STR (18.9% vs 9.8%, p=0.009). After adjusting for clinical and angiographic risk profiles, multivariate analysis showed that age ≥75 years remained independently associated with reduced TMPG or absent STR. In the whole population, multivariate analysis revealed that both age ≥75 years and absent STR were independently associated with 3-month major adverse cardiac events (MACE). In the elderly subgroup, multivariate analysis identified absent STR as the strongest determinant of 3-month MACE. CONCLUSIONS Age is associated with impaired myocardial perfusion, but not epicardial perfusion, after PPCI for AMI. To further improve the outcome of elderly AMI patients, efforts should be aimed at improving myocardial perfusion beyond epicardial recanalization.