Worldwide prevalence of diabetes is found to be the human health at an alarming rate. However, large numbers of patient remain undiagnosed. Oral glucose tolerance test (OGTT) still is regarded as gold standard in diagnosis of blood glucose abnormality. Although the less number of bodies are considering measurement of HbA1C as an alternate tool to identify risk group. This study was undertaken to evaluate the role of measurement of HbA1C in the diagnosis of diabetes and pre-diabetes in middle-aged Bangladeshi subjects and carried out in the department of Biochemistry, BIRDEM from July 2013 to June 2014. A total 177 subjects of age within the range of 30-45 years were selected for the purpose and classified into healthy control (n=62) pre-diabetes (n=69) and diabetes (n=46) groups based on the values of OGTT. Middle aged Bangladeshi subjects attending Bangladesh Institute of Research & Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM) hospital, the HbA1C values were 5.0-5.6% in control group, 5.6-6.2% in pre-diabetes and 8.1-9.7% in diabetes group (95% CI). The optimal cut-off value of HbA1C related to pre-diabetes diagnosed by OGTT was 5.6%, which showed the sensitivity 47.8%, specificity 74.2%, positive predictive value 67.3% and negative predictive value 58.5%. Variants of hemoglobin especially Hemoglobin E (HbE) is prevalent in South East Asia including Bangladesh. The presence of genetic variants of hemoglobin can profoundly affect the accuracy of HbA1C measurements. So measurement of HbA1C may not be used as an alternate tool of OGTT to identify people of diabetes and pre-diabetes in certain situation.