Background Heart failure (HF) is a progressive condition and repeated hospitalizations are associated with worse outcomes. Guideline-directed medical therapy (GDMT) is proven to reduce morbidity and mortality however previous literature has demonstrated low rates of prescribing. In April 2017, the ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guidelines for the Management of Heart Failure provided a clarified recommendation supporting the clinical strategy of renin-angiotensin system inhibition through angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs) or angiotensin receptor-neprilysin inhibitors (ARNIs) in conjunction with evidence-based beta blockers and aldosterone antagonists in select heart failure with reduced ejection fraction (HFrEF) patients. We aimed to evaluate prescriber adherence rates to GDMT in patients hospitalized with acute decompensated heart failure (ADHF) at time of discharge after the publication of the guideline update. Methods A retrospective chart review of HF admissions at a large urban academic health system was conducted between October 1, 2017 and December 31, 2017. Patients 18 years or older with a left ventricular ejection fraction of 40 percent or less were included. Patients were excluded if they had a left ventricular assist device, heart transplant, end-stage renal disease on hemodialysis or were dependent on inotropes. Criteria for appropriate GDMT use were developed to guide data collection based off the 2017 ACC/AHA/HFSA Focused Update. The primary outcome was prescriber adherence to GDMT determined by prescriptions written at the time of discharge or documented on the discharge summary. Secondary outcomes included 30-day all-cause readmission rate and guideline adherence by provider service. Results Of the 50 patients reviewed only 32% (n=16) were discharged on appropriate GDMT. Table 1 depicts the percent of eligible patients receiving therapy upon discharge by drug class. Guideline adherence among the internal medicine service was 33.3% (12/36) compared to 28.5% (4/14) among the cardiology service. The 30-day readmission rate was lower among those discharged on appropriate therapy versus inappropriate therapy (25% vs. 46%). Conclusion Despite over 20 years of evidence and recently published guideline updates our results demonstrate poor prescriber adherence to GDMT with an alarmingly low number of eligible patients receiving aldosterone antagonists and appropriate combination therapy. Health systems must recognize and address barriers to guideline adherence in order to improve outcomes for HF patients.