There is limited large, national data investigating the prevalence, characteristics, and outcomes of cardiac arrest (CA) in patients hospitalized for heart failure (HF). The goal of this study was to examine the characteristics, trends, and outcomes of HF hospitalizations complicated by in-hospital CA. We used the National Inpatient Sample to identify all primary HF admissions from 2016 to 2019. Cohorts were built based on the presence of a codiagnosis of CA. Diagnoses were identified using International Classification of Diseases, Tenth Revision, Clinical Modification codes. Associations with CA were then analyzed using multivariate logistic regression. We identified a total of 4,905,564 HF admissions, 56,170 (1.1%) of which had CA. Hospitalizations complicated by CA were significantly more likely to be male, to have coronary artery disease, renal disease, and less likely to be White (p <0.001, all). Age <65 (odds ratio [OR] 1.18, p <0.001), renal disease (OR 2.41, p <0.001), and coronary artery disease (OR 1.26, p <0.001) had higher odds of CA while female gender (OR 0.84, confidence interval [CI] 0.83 to 0.86, p <0.001) or HFpEF (OR 0.49, CI 0.48 to 0.50, p <0.001) had lower odds of CA. Patients with CA had higher inpatient mortality (CA 54.2% vs no CA 2.1%, p <0.001), which persisted after multivariate adjustment (OR 64.8, CI 63.5 to 66.0, p <0.001). CA occurs in >1 in 1,000 HF hospitalizations and remains a prominent and serious event associated with a high mortality. Further research is needed to examine long-term outcomes and mechanical circulatory support utilization with more granularity in HF patients with in-hospital CA.