Background: The term prediabetes refers to people who have impaired fasting glucose (100-125 mg/dL), impaired glucose tolerance (2-hour postglucose load of 140-199 mg/dL), or both. If prediabetes is not detected, the progression to type 2 diabetes mellitus is not inevitable. So treament is more expensive and increment complications. Objectives: To identify the prevalence of prediabetes, diabetes in outpatient department of Bach mai hospital. Methods: A cross - sectional, descriptive study was carried out on 1054 persons, from 30 to 69 years ago, who check health in outpatient department of Bach mai hospital from 2 to 10/2012, implemented Oral glucose tolerance test and diagnose prediabetes according to criteria of WHO - 1999. Results: The prevalence of prediabetes is 38 percent. The prevalence of diabetes is 9 percent.