Background: Guideline-directed medical therapies for heart failure (HF) may benefit patients with reduced left ventricular ejection fraction (LVEF) following acute coronary syndromes (ACS). Few real-world data are available regarding the early implementation of HF therapies in patients with ACS and reduced LVEF. Methods: Data collected from the 2021 nationwide, prospective ACS Israeli Survey (ACSIS). Drug classes included: (a) angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB) or angiotensin receptor-neprilysin inhibitors (ARNI); (b) beta-blockers; (c) mineralocorticoid receptor antagonist (MRA) and (d) sodium-glucose cotransporter-2 inhibitors (SGLT2I). The utilization of HF therapies at discharge or 90 days following ACS was analyzed in relation to LVEF [reduced ≤40% (n= 406) or mildly-reduced 41–49% (n= 255)] and short-term adverse outcomes. Results: History of HF, anterior wall myocardial infarction and Killip class II-IV (32% vs. 14%p< 0.001) were more prevalent in those with reduced compared to mildly-reduced LVEF. ACEI/ARB/ARNI and beta-blockers were used by the majority of patients in both LVEF groups, though ARNI was prescribed to only 3.9% (LVEF ≤ 40%). MRA was used by 42.9% and 12.2% of patients with LVEF ≤40% and 41–49%, respectively, and SGLT2I in about a quarter of both LVEF groups. Overall, ≥3 HF drug classes were documented in 44% of the patients. A trend towards higher rates of 90-day HF rehospitalizations, recurrent ACS or all-cause death was noted in those with reduced (7.6%) vs. mildly-reduced (3.7%) LVEF,p= 0.084. No association was observed between the number of HF drug classes or the use of ARNI and/or SGLT2I with adverse clinical outcomes. Conclusions: In current clinical practice, the majority of patients with reduced and mildly-reduced LVEF are treated by ACEI/ARB and beta-blockers early following ACS, whereas MRA is underutilized and the adoption of SGLT2I and ARNI is low. A greater number of therapeutic classes was not associated with reduced short-term rehospitalizations or mortality.