The aim of this study was to describe the agreement between impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) in children with excess body weight using the original and the revised definitions of IFG. Obese and overweight children aged 4-17 years were included (n = 533). Anthropometric parameters and biochemical tests (fasting and 2-h glucose tests after an oral glucose load [1.75 g/kg]) were performed. Case subjects with a fasting plasma glucose >/=126 mg/dl were excluded. The diagnostic parameters of the original and the revised definitions of IFG for detecting IGT were estimated. The analysis of agreement between these categories was made using the kappa test. The prevalence of IFG increased from 6.2 to 13.3% using the new criteria. The prevalence of IFG became closer to the prevalence of IGT (14.8%). The revised criteria increased the sensitivity from 26.6 to 36.7%. However, the new IFG definition was not useful for identifying IGT cases. Of the 71 case subjects with IFG, only 29 (40.8%) had IGT. In addition, 50 case subjects with IGT (9.4%) and 13 with diabetes (2.4%) had a fasting glycemia