Background and Purpose-Diabetes mellitus (DM) is an independent risk factor for ischemic stroke. However, controversy exists with regard to the impact of DM on prognosis after ischemic stroke in the Chinese population. We investigated the associations between DM and death, dependency, and stroke recurrence in patients after ischemic stroke onset in a nationwide, prospective registry, the China National Stroke Registry. Methods-The China National Stroke Registry consecutively recruited patients hospitalized for acute ischemic stroke in 2007 to 2008 and who were prospectively followed up for clinical and functional outcomes (death, dependency, and stroke recurrence) at 3 and 6 months after disease onset. Multivariable logistic regression was performed to analyze the association between DM and stroke outcomes after adjusting for potential confounding including age, sex, National Institutes of Health Stroke Scale score, glucose level at admission, hypertension, coronary heart disease, smoking, urinary tract infection, and other factors. Results-DM was identified in 3483 (27.0%) of stroke patients. Compared with stroke patients without DM, patients with DM had a significantly higher incidence of death or dependency and of recurrent stroke at 3 and 6 months after stroke onset. DM was an independent risk factor for death or dependency (adjusted odds ratio = 1.23; 95% confidence interval, 1.10 to 1.37) in patients with ischemic stroke at 6 months after onset. Conclusions-DM independently predicted poor outcomes in Chinese patients after acute ischemic stroke. (Stroke. 2011; 42: 2758-2762.)