Aim: The aim of this study is to correlate the A1C values with the OGTT in individuals without type 2 Diabetes (DM) but with impaired fasting glucose (IFG) (FPG: 5.6-6.9mmol/l). Methods:We investigated 119 subjects with IFG divided according to A1C levels (<5.7%; 5.7-6.4%, ≥6.5%) and analyzed the correlation among A1C, FPG and 2-hPG by Pearson's coefficient. Kappa coefficient was used to test agreement between A1C and 2-hPG for the diagnosis of DM. Results:The average age of the subjects was 54.2 ± 14.6 years, the average BMI was 30.2 ±5.5 and 70.5% were women. While levels of A1C ≥6.5% were associated to alterations in the 2-hPG in 86.7%, only 28.6% of these patients had 2-hPG >11.1mmol/l. Furthermore, 31.6% of the patients with DM diagnosed by the OGTT had A1C levels ≥6.5% and 64.3% of the patients with A1C < 5.7% had a normal OGTT. The Kappa coefficient of reliability between A1C and 2-hPG to diagnose DM was 0.71. Conclusion:A1C is a useful tool in evaluating IFG patients and correlates better to 2-hPG than to FPG. Yet, the agreement between A1C and OGTT to diagnose DM in this group was moderate (71%). It may be too soon to consider A1C as a substitute exam for OGTT.