Background Patients presenting to hospitals during non-weekday hours experience worse outcomes, often attributed to reduced staffing. The American Heart Association International Stroke Conference ( ISC ) is well attended by stroke clinicians. We sought to determine whether patients with acute ischemic stroke ( AIS ) admitted during the ISC receive less guideline-adherent care and experience worse outcomes. Methods and Results We performed a retrospective cohort study of US hospitals participating in Get With The Guidelines-Stroke and assessed use of intravenous tissue plasminogen activator, other quality measures, and outcomes for patients with AIS admitted during the ISC compared with those admitted the weeks before and after the conference. A total of 69 738 patients with AIS were included: mean age, 72 years; 52% women; 29% nonwhite. There was no difference between the average weekly number of AIS cases admitted during ISC weeks versus non- ISC weeks (1984 versus 1997; P=0.95). Patient and hospital characteristics were similar between ISC and non- ISC time periods. There were no significant differences in 14 quality metrics and 5 clinical outcomes between patients with AIS treated during the ISC versus non- ISC weeks. Patients with AIS who presented within 2 hours of onset had no difference in the likelihood of receiving intravenous tissue plasminogen activator within 3 hours (adjusted odds ratio, 0.89; 95% confidence interval, 0.77-1.03; P=0.13) or the likelihood of receiving intravenous tissue plasminogen activator within 60 minutes of arrival (adjusted odds ratio, 0.92; 95% confidence interval, 0.83-1.02; P=0.13). Conclusions Patients with acute stroke admitted to Get With The Guidelines-Stroke hospitals during ISC received the same quality care and had similar outcomes as patients admitted at other times.