As part of a prospective study about 347 cases of ischemic cerebral vascular disease (DCVI) admitted to a general hospital 36 diabetic and 36 non-diabetic patients with similar sex, age and blood pressure were evaluated with the objective of assessing the effect of diabetes mellitus on prognosis in DCVI. All patients had various types of DCVI (thrombosis, thromboembolism or cardiac embolism). The diabetic patients had statistically longer admissions (p less than 0.05), more complications during admission (p less than 0.05), more infectious complications (p less than 0.01) and a greater number of deaths at the end of follow-up (p less than 0.05). After 377 +/- 429 (mean +/- standard deviation) days of follow-up, 50% of the diabetics had died while after 387 +/- 405 days 25% of the non-diabetics had died. Deaths in both groups occurred in average at the 8th month after the vascular event that led to the first admission. There were no differences with respect to the number of deaths during admission or to neurological conditions of the survivors at the end of the first admission or at the end of follow-up.