© 2018 American Medical Association. All rights reserved. Importance: Get With The Guidelines-Stroke (GWTG-Stroke) is an American Heart Association/American Stroke Association stroke-care quality-improvement program; however, to our knowledge, there has not been a direct comparison of the quality of care between patients hospitalized at participating hospitals and those at nonparticipating hospitals. Objective: To contrast quality of stroke care measures for patients admitted to hospitals participating and not participating in GWTG-Stroke. Design, Setting, and Participants: Subpopulation of 546 participants with ischemic stroke occurring during a 9-year follow-up of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a population-based cohort study of 30239 randomly selected black and white participants 45 years and older recruited between 2003 and 2007. Of those with stroke, 207 (36%) were treated in a hospital participating in GWTG-Stroke and 339 in a nonparticipating hospital. Data were analyzed between July 29, 2017, and April 17, 2018. Main Outcomes and Measures: Quality of care measures including use of tissue plasminogen activator, performance of swallowing evaluation, antithrombotic use in first 48 hours, lipid profile assessment, discharge receiving antithrombotic therapy, discharge receiving a statin, neurologist evaluation, providing weight loss and exercise counseling, education on stroke risk factors and warning signs, and assessment for rehabilitation. Results: Participants treated at participating hospitals had a mean (SD) age of 74 (8) years and 100 of 207 were men (48%), while those seen at nonparticipating hospitals had a mean (SD) age of 73 (9) years, and 161 of 339 were men (48%). Those seen in participating hospitals were more likely to receive 5 of 10 evidence-based interventions recommended for patients hospitalized with ischemic stroke, including receiving tissue plasminogen activator (RR, 3.74; 95% CI, 1.65-8.50), education on risk factors (RR, 1.54; 95% CI, 1.16-2.05), having an evaluation for swallowing (RR, 1.25; 95% CI, 1.04-1.50), a lipid evaluation (RR, 1.18; 95% CI, 1.05-1.32), and an evaluation by a neurologist (RR, 1.12; 95% CI, 1.05-1.20). Those seen in participating hospitals received a mean of 5.4 (95% CI, 5.2-5.6) interventions compared with 4.8 (95% CI, 4.6-5.0) in nonparticipating hospitals (P <.001). Conclusions and Relevance: These data collected independently of the GWTG-Stroke program document improved stroke care for patients with ischemic stroke hospitalized at participating hospitals.