Introduction: The impact of frailty on outcomes in a contemporary ST-segment-elevation myocardial infarction (STEMI) population is unclear. This study hypothesized that frail STEMI patients undergoing primary percutaneous coronary intervention (pPCI) have worse in-hospital and 1-year outcomes compared to non-frail STEMI patients. Methods: We retrospectively identified 600 STEMI patients who had received pPCI (2013 - 2016). A frailty index (FI) was determined using the health deficit accumulation model (Table 1). Frail patients were defined as those with a FI > 0.25. The composite outcome comprised in-hospital heart failure, cardiogenic shock, re-infarction, major bleeding, stroke and all-cause mortality. A multivariable model adjusting for age and sex was performed. Results: Among 600 STEMI patients receiving pPCI, 67 (11.2%) were classified as frail. Compared to non-frail patients, frail patients were older (mean 80.3 vs. 75.8 years, p < 0.001) and had a higher comorbidity burden. After adjustment, baseline frailty was independently associated with delayed reperfusion time, in-hospital all-cause mortality, and higher incidence of the composite outcome (Figure 1). Frailty was also associated with increased 1-year all-cause mortality and cardiovascular rehospitalization. Conclusions: Among STEMI patients receiving pPCI, 1 in 10 were frail. Frailty was associated with increased rate of the primary in-hospital composite adverse outcome, delayed reperfusion time and worse long-term outcomes. Efforts to routinely identify frail STEMI patients and to implement best practices to reduce the risk of adverse events in this vulnerable population are warranted.