Background and Purpose-The prevalence of diabetes is high among patients with ischemic stroke. However, the prevalence of abnormal glucose regulation and clinical characteristics among patients with stroke in the Chinese population is uncertain. We investigated the prevalence of prediabetes and diabetes in Chinese patients after stroke onset in a nationwide cohort study and investigated abnormal glucose regulation in patients with acute stroke across China (ACROSS-China). Methods-The ACROSS-China study consecutively recruited patients hospitalized for acute stroke in 2008 to 2009 and investigated the prevalence of impaired glucose tolerance and diabetes among the patients on day 14 after stroke onset. Oral glucose tolerance test was performed in the diagnosis of abnormal glucose regulation. Results-The prevalence of abnormal glucose regulation was 68.7% among all the patients with stroke. Diabetes was identified in 42.3% of all the patients (45.8% for patients with ischemic stroke, 31.2% for patients with intracerebral hemorrhage, and 26.4% for patients with subarachnoid hemorrhage, respectively). Prediabetes (impaired fasting glucose and impaired glucose tolerance) was identified in 26.4% of all the patients with stroke. The prevalence of diabetes and impaired glucose tolerance was the highest in the patients with atherothrombotic infarction (73.4%). Conclusions-The prevalence of abnormal glucose regulation was high in Chinese patients with acute stroke, especially in patients with atherothrombotic infarction. Oral glucose tolerance test identified a large percentage of patients with newly diagnosed diabetes or impaired glucose tolerance after stroke onset. (Stroke. 2012; 43: 650-657.)