Importance: Cardiovascular disease is a major cause of death among homeless adults, with mortality rates that are substantially higher than in the general population. It is unknown whether differences in hospitalization-related care contribute to these disparities in cardiovascular outcomes. Objective: To evaluate differences in intensity of care and mortality between homeless and nonhomeless individuals hospitalized for cardiovascular conditions (ie, acute myocardial infarction, stroke, cardiac arrest, or heart failure). Design, Setting, and Participants: This retrospective cross-sectional study included all hospitalizations for cardiovascular conditions among homeless adults (n = 24890) and nonhomeless adults (n = 1827900) 18 years or older in New York, Massachusetts, and Florida from January 1, 2010, to September 30, 2015. Statistical analysis was performed from February 6 to July 16, 2019. Main Outcomes and Measures: Risk-standardized diagnostic and therapeutic procedure rates and in-hospital mortality rates. Results: Of the 1852790 total hospitalizations for cardiovascular conditions across 525 hospitals, 24890 occurred among patients who were homeless (11452 women and 13438 men; mean [SD] age, 65.1 [14.8] years) and 1827900 occurred among patients who were not homeless (850660 women and 977240 men; mean [SD] age, 72.1 [14.6] years). Most hospitalizations among homeless individuals were primarily concentrated among 11 hospitals. Homeless adults were more likely than nonhomeless adults to be black (38.6% vs 15.6%) and insured by Medicaid (49.3% vs 8.5%). After accounting for differences in demographics (age, sex, and race/ethnicity), insurance payer, and clinical comorbidities, homeless adults hospitalized for acute myocardial infarction were less likely to undergo coronary angiography compared with nonhomeless adults (39.5% vs 70.9%; P <.001), percutaneous coronary intervention (24.8% vs 47.4%; P <.001), and coronary artery bypass graft (2.5% vs 7.0%; P <.001). Among adults hospitalized with stroke, those who were homeless were less likely than nonhomeless individuals to undergo cerebral angiography (2.9% vs 9.5%; P <.001) but were as likely to receive thrombolytic therapy (4.8% vs 5.2%; P =.28). In the cardiac arrest cohort, homeless adults were less likely than nonhomeless adults to undergo coronary angiography (10.1% vs 17.6%; P <.001) and percutaneous coronary intervention (0.0% vs 4.7%; P <.001). Risk-standardized mortality was higher for homeless persons with ST-elevation myocardial infarction compared with nonhomeless persons (8.3% vs 6.2%; P =.04). Mortality rates were also higher for homeless persons than for nonhomeless persons hospitalized with stroke (8.9% vs 6.3%; P <.001) or cardiac arrest (76.1% vs 57.4%; P <.001) but did not differ for heart failure (1.6% vs 1.6%; P =.83). Conclusions and Relevance: There are significant disparities in in-hospital care and mortality between homeless and nonhomeless adults with cardiovascular conditions. There is a need for public health and policy efforts to support hospitals that care for homeless persons to reduce disparities in hospital-based care and improve health outcomes for this population.