BACKGROUND: Neighborhood socioeconomic status (SES) is associated with worse health outcomes, yet its relationship with in-hospital heart failure (HF) outcomes and quality metrics are underexplored. We examined the association between socioeconomic neighborhood disadvantage and in-hospital HF outcomes for patients from diverse neighborhoods in the Get With The Guidelines-Heart Failure registry. METHODS: SES-disadvantage scores were derived from geocoded US census data using a validated algorithm, which incorporated household income, home value, rent, education, and employment. We examined the association between SES-disadvantage quintiles with all-cause in-hospital mortality, adjusting for demographics and comorbidities. RESULTS: Of 593 053 patients hospitalized for HF between 2017 and 2020, 321 314 (54%) had residential ZIP Codes recorded. Patients from the most compared with least disadvantaged neighborhoods were younger (mean age 67 versus 76 years), more often Black (42% versus 9%) or Hispanic (14% versus 5%), and had higher comorbidity burden. Demographic-adjusted length of stay increased by ≈1.5 hours with each increment in worsening SES-disadvantage quintiles. Adjusted-mortality odds ratios increased with worsening SES-disadvantage quintiles (Ptrend=0.003), and was 28% higher (adjusted OR=1.28 [1.12-1.48]) for the most compared with least disadvantaged neighborhood groups. CONCLUSIONS: Patients hospitalized for HF from disadvantaged neighborhoods were younger and more often Black or Hispanic. SES disadvantage was independently associated with higher in-hospital mortality. Further research is needed to characterize care delivery patterns in disadvantaged neighborhoods and to address social determinants of health among patients hospitalized for HF. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02693509.