- Treatment delays in patients with acute myocardial infarction (AMI) are related to increased morbidity and mortality. Hence, identifying determinants of delay may help reduce time to treatment. Importantly, limited data suggest that there may be sex-related disparities in benchmark timelines. Although guidelines advocate the use of the first medical contact (FMC) rather than hospital admission as the moment from which delays to treatment should be monitored, the latter is still often used for quality purposes. We aimed to identify factors associated with treatment delays, with an emphasis on sex-related disparities. We reviewed data on 3,658 patients with AMI from 2 contemporary, consecutive multicenter surveys. Measured delays were FMC-to-electrocardiogram >10 minutes in ST-elevation MI (STEMI) and non-STEMI, FMC-to-primary percutaneous coronary intervention >90 minutes in STEMI, and invasive angiography >72 hours after admission in non-STEMI patients. Timely electrocardiogram was performed in 48% of patients with STEMI and in 39.8% of non-STEMI patients without significant sex-related differences. Independent determinants of delay included atypical chest pain (CP) and presentation during daytime. In patients with STEMI, 37.5% had primary percutaneous coronary intervention in less than 90 minutes without significant sex-related disparities. Independent determinants of delay included atypical CP, night presentation, and diabetes. In non-STEMI patients, independent determinants of delayed invasive approach were female sex, age >75 years, atypical CP, and renal failure. In conclusion, significant treatment delays in patients with AMI are still frequent in contemporary practice, highlighting the need for improvement and guidelines implementation. Predictors of delay identified in our study may facilitate targeting of interventions to improve adherence to guidelines.