Despite its clinical benefits, aspirin has been considered one of the predictors of worse outcomes in patients with unstable angina/non-ST-segment-elevation myocardial infarction. Nevertheless, such association has not been demonstrated in patients with ST-elevation myocardial infarction (STEMI). Five hundred eighty-six STEMI patients undergoing primary percutaneous coronary intervention were evaluated including 116 prior aspirin users. Angiographic characteristics and 1-year major adverse cardiac events (MACE) were then compared between the 2 groups. Adjusted analysis showed that the prior aspirin users had a significantly higher rate of totally occluded infarct-related artery before primary percutaneous coronary intervention (odds ratio: 1.859; P = 0.019). Postprocedural Thrombolysis in Myocardial Infarction flow grade 3 was less often demonstrated in the prior aspirin users (odds ratio: 1.512; P = 0.059). Aspirin consumption was associated with increased long-term mortality and MACE. Prior aspirin users had higher rate of MACE and worse pre- and postprocedural angiographic features. We suppose that patients who develop STEMI despite long-term aspirin intake probably reflect more vulnerable pre-existing coronary plaques with more thrombogenicity, which could negatively affect long-term cardiovascular outcomes.