Abstract Background/Introduction European guidelines strongly recommend an optimized pharmacological treatment in patients with heart failure with reduced ejection fraction (HFrEF) with a fast introduction of the four-pillars. Purpose Aim of the Optimization of Therapy in the Italian Management of Heart Failure [OpTIMa-HF] Registry was to collect data on HF patients to describe the current Italian population of HF patients with a specific focus on HFrEF treatment adherence and prescription rates, according to the most recent European Guidelines. Methods OPTIMA-HF is an observational, cross-sectional, multicenter, real-life study conducted in two different clinical settings: HF outpatients’ clinics of Italian University Hospitals and territorial Italian Cardiology outpatients’ services, that enrolled patients with chronic HFrEF receiving at least 1 oral medication for management of HF. Patients were characterized by baseline use and dose of angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB)/angiotensin receptor neprilysin inhibitor (ARNI), beta-blocker, mineralocorticoid receptor antagonist (MRA) and sodium glucose co-transporter II inhibitor (SGLT2i). Patient-level factors associated with medication use were examined. Results Overall, 1390 patients from 29 ambulatory cardiology practices and university hospitals were included. Mean age was 69.5 ± 11.9 years, 24% were female, and median EF was 33 (28-37). Among enrolled patients, 72.2% were prescribed ARNI, 17.1% ACEI/ARB, 95% beta-blocker, 75.5% MRA and 63% SGLT2i therapy (Figure 1). Despite high prescription rates for each single class, a still not sufficient number of patients was on treatment with all four pillars, in particular 40.4% considering the presence ARNI and 6.2%. When medications were prescribed, few patients were receiving target doses of ACEI/ARB (31.7%), ARNI (16%), and beta-blocker (33.3%), whereas a higher proportion were receiving target doses of MRA therapy (38%), and all were receiving target dose for SGLT2i. Among patients eligible for all classes of medication, only 1.1% were simultaneously receiving target doses of ACE/ARB/ARNI, beta-blocker, MRA and SGLT2i. Prescription rates did not significantly differ between the type of center (University Hospital vs. territorial Cardiology outpatients’ services). As regards patients not on treatment with any of the four pillars, a small but still present amount of patients had no contraindications to these drugs (Figure 1). Conclusions In this contemporary outpatient HFrEF Italian registry, significant high prescription rates of the four-pillars were observed, however therapy combination rate is still not sufficient and drugs' titration need to be implemented to receive the greatest benefits from an optimized treatment. Strategies to improve guideline-directed use of HFrEF medications remain urgently needed, and these findings may inform targeted approaches to optimize outpatient medical therapy.