Interest in home-based care is increasing among Medicare Advantage (MA) plans. The epidemiology of homebound MA beneficiaries is unknown. To determine the prevalence, characteristics, predictors, health service use, and mortality outcomes of homebound beneficiaries of a large national MA plan. Cross-sectional. National MA plan. Humana MA beneficiaries in 2022 (n = 2 435 519). Homebound status was assessed via in-home assessment using previously defined categories: homebound (never or rarely left home in the past month), semihomebound (left home with assistance, had difficulty, or needed help leaving home), and not homebound. Demographic, clinical, health service use, and mortality outcomes were compared by homebound status. In 2022, the overall prevalence of homebound beneficiaries was 22.0% (8.4% of beneficiaries were homebound, and 13.6% were semihomebound). In adjusted models, female sex (odds ratio [OR], 1.36 [95% CI, 1.35 to 1.37), low-income status or dual eligibility for Medicare and Medicaid (OR, 1.56 [CI, 1.55 to 1.57]), dementia (OR, 2.36 [CI, 2.33 to 2.39]), and moderate to severe frailty (OR, 4.32 [CI, 4.19 to 4.45]) were predictive of homebound status. In multivariable logistic regression, homebound status was associated with increased odds of any emergency department visit (OR, 1.14 [ CI, 1.14 to 1.15]), any inpatient hospital admission (OR, 1.44 [CI, 1.42 to 1.46]), any skilled-nursing facility admission (OR, 2.18 [CI, 2.13 to 2.23]), and death (OR, 2.55 [CI, 2.52 to 2.58]). The study period overlapped the tail end of the COVID-19 pandemic, and data were derived from a single national MA plan, which limits generalizability. Overall homebound prevalence in a national MA plan was 22.0% and was independently associated with increased health service use and mortality. Study findings can inform strategic initiatives to identify and manage care for homebound beneficiaries. Humana, under a collaborative research agreement with Johns Hopkins University.