ABSTRACT: Background:The impact of sex on the outcome of patients with acute coronary syndrome (ACS) has been suggested, but little is known about its impact on elderly patients with ACS. Methods:This study analyzed the impact of sex on in-hospital and 1-year outcomes of elderly (?75 years of age) patients with ACS hospitalized in our department between January 2013 and December 2017. Results:A total of 711 patients were included: 273 (38.4%) women and 438 (61.6%) men. Their age ranged from 75 to 94 years, similar between women and men. Women had more comorbidities (hypertension (79.5% vs. 72.8%, p=0.050), diabetes mellitus (35.2% vs. 26.5%, p=0.014), and hyperuricemia (39.9% vs. 32.4%, p=0.042)) and had a higher prevalence of non-ST-segment elevation ACS (NSTE-ACS) (79.5% vs. 71.2%, p=0.014) than men. The prevalence of current smoking (56.5% vs. 5.4%, p < 0.001), creatinine levels (124.4?±?98.6 vs. 89.9?±?54.1, p < 0.001), and revascularization rate (39.7% vs. 30.0%, p=0.022) were higher, and troponin TnT and NT-proBNP tended to be higher in men than in women. The in-hospital mortality rate was similar (3.5% vs. 4.4%, p=0.693), but the 1-year mortality rate was lower in women than in men (14.7% vs. 21.7%, p=0.020). The multivariable analysis showed that female sex was a protective factor for 1-year mortality in all patients (OR?=?0.565, 95% CI 0.351-0.908, p=0.018) and in patients with STEMI (OR?=?0.416, 95% CI 0.184-0.940, p=0.035) after adjustment. Conclusions:Among the elderly patients with ACS, the 1-year mortality rate was lower in women than in men, which could be associated with comorbidities and ACS type.