Introduction: Impaired glucose tolerance, an intermediate metabolic state between normal glucose levels and diabetes is associated with an increased stroke risk. The aim of this study was to determine the prevalence of impaired glucose metabolism in patients with acute stroke who had normal fasting plasma glucose.Methods: Eligible subjects were non diabetic patients with ischemic stroke, from April 2005 to April 2006, who were evaluated eight weeks after their stroke event for FBS, GTT, HbA1C and serum insulin level (HOMA); the correlation of these tests with the number of stroke risk factors among the patients was assessed.Results: Among 58 patients, 18 of them did not complete the study. In GTT evaluation in 40 patients, 26 of them (65%) had normal test values while 10 patients (25%) showed impaired tolerance and 4 (10%) were diabetic. Overall, 35% of them had impaired glucose metabolism. In HbA1C analysis only 15% had abnormal test results. The mean of HOMA in our patients was 1.7 (1.64 to 2.16 in the normal group compared with the impaired one, respectively). In the FBS study, previously undiagnosed DM patients, impaired glucose tolerance patients and non diabetic ones account for 10, 25, and 65% of all cases respectively.Discussion: Impaired glucose metabolism is one of the important risk factors for stroke and if only fasting plasma glucose is used for screening patients, at least 10% of patients prone to the side effects of hyperglycemia, will be missed.Conclusion: This study shows that in patients with no history of diabetes who have an ischemic stroke, even moderately elevated glucose levels are associated with both a higher risk of short-term mortality and an increased risk of poor functional recovery compared with lower glucose levels.