Objective: The relationship between diabetes and stroke is not completely understood. This study evaluated stroke risk and post-stroke mortality in patients with diabetes. Methods: We identified 24,027 adults newly diagnosed with diabetes in 2000~2003 using Taiwan’s National Health Insurance Research Database. A comparison cohort of 96,108 adults without diabetes was randomly selected from the same dataset, with frequency matched by age and sex. Stroke events in 2000~2008 were ascertained from medical claims. Adjusted hazard ratios (HRs) and 95% CIs of stroke associated with diabetes were calculated. A nested cohort study of 22,348 hospitalized stroke patients between 2000 and 2009 calculated adjusted odds ratios (ORs) and 95% CIs of adverse events after stroke in patients with and without diabetes. Results: During 821,563 person-years of follow-up, there were 4,629 newly diagnosed stroke cases. The incidences of stroke for people with diabetes and without were 10.1 and 4.5 per 1,000 person-years, respectively (P < 0.0001). Compared with people without diabetes, the adjusted HR of stroke was 1.75 (95% CI 1.64~1.86) for people with diabetes. The ORs of post-stroke pneumonia, urinary tract infection, and mortality associated with diabetes were 1.28 (95% CI 1.10~1.37), 1.57 (95% CI 1.44~1.71), and 1.59 (95% CI 1.36~1.87), respectively. Conclusion: Diabetes was associated with stroke. Patients with diabetes had more adverse events and subsequent mortality after stroke. Prevention of stroke and post-stroke adverse events is needed in this susceptible population.