Abstract： ObjectiveTo explore the effect of diabetes melli tus (DM) on the clinical characteristics and the prognosis of patients with isch emic stroke.MethodsA retrospective study was performed to an alyze the clinical characteristics of all patients with ischemic stroke who were hospitalized from November 1999 to October 2001 in the department of neurology. Diffusion weighted image (DWI) of MRI was used to compare the location and size of lesions in ischemic stroke patients with and without DM. All patients were f ollowed to learn about the rate of recurrent stroke and the survival rate after hospitalization.ResultsThe history of DM was strongly associ ated with the size of new infarctive lesions on DWI (P<0.01), but not with t he localization(P>0.05). Life table analysis revealed that the recurrent s troke rate was significantly higher in patients with DM than in those without DM (P<0.01,Log Rank test), but no relationship was found between the surviv al rate the history of DM (P>0.05,Log Rank test). Cox proportional hazards model showed the OR of recurrent stroke rate was 2.8 in patients with DM. We al so found the patients with a history of DM over 5 years were more likely to get recurrent stroke compared with those less than 5 years(P<0.05).C onclusionOur study demonstrated that DM can not only effect on the siz e of cerebral infarcts but also the recurrent stroke rate in patients with ische mic stroke; and the recurrent stroke rate may also be associated with the durati on of DM.