To compare angiographic characteristics and outcomes of primary percutaneous coronary intervention between young and old patients presenting with acute ST Elevation Myocardial Infarction.The prospective observational study was conducted at the National Institute of Cardiovascular Diseases, Karachi, from December 17, 2016, to June 16, 2017, and comprised acute ST-Elevation Myocardial Infarction patients undergoing primary percutaneous coronary intervention (PCI). Data was collected on demographic, angiographic, and in-hospital outcomes. Those <40 years were considered young. Data was analysed using SPSS 21.Of the 415 patients, 50(12%) were young. Proportion of male was higher among the young (p=0.02) and so was the case with positive family history (p=0.002). The young had lesser cases of diabetes (p=0.028) and hypertension (p=0.034). Single vessel disease was more common among young (p<0.001). No significant difference was observed in post-procedure outcome related to age (p>0.05).Acute Myocardial Infarction in young was more likely associated with male gender, positive family history and less likely with hypertensive and diabetic status.