Object: This study aimed to examine the impaired glucose tolerance in patients with dementia. Subjects and Methods: There were two groups: dementia group: 60 patients, diagnosed according to DSM-IV-TR criteria. Control group: 60 subjects without dementia. All subjects were examined and performed neurological tests and oral glucose tolerance test (OGTT). Results: the average 2h blood glucose. concentration in dementia group was statistically significant higher than those in control group (8.24 + or - 2.59 mmol/L compared with 7.41 + or - 1.51 mmol/L , p 0,05). The proportion of impaired glucose tolerance in dementia group was 43.3 percent, the rate of newly diagnosed diabetes detected by OGTT in dementia group was 11.7 percent. Impaired glucose tolerance in dementia was higher than that in control group (p 0.001). Risks for dementia in patients with impaired glucose tolerance were 10 times higher than those without impaired glucose tolerance. No differences in impaired fasting glucose in both groups (p0,05). Conclusion: Glucose intolerance was common in patients with SSTT and could be considered as independent risk of dementia, therefore, screening for impaired glucose intolerance is valuable in the early diagnosis and monitoring of dementia progression.