The aim of this study was to compare the ability of the metabolic syndrome (MetS) and fasting and 2-h glucose to predict progression to diabetes in non-diabetic first-degree relatives (FDRs) of patients with type 2 diabetes.A total of 706 non-diabetics FDR 20–70 years old in 2003–2005 were followed through 2008 for the occurrence of type 2 diabetes mellitus. At baseline and through follow-ups, participants undergo a standard 75g 2-h oral glucose tolerance test. MetS was defined by NCEP-ATP III.The fasting and 2-h glucose values were better predictors of progression to diabetes than MetS. Compared to participants without MetS, the age-adjusted relative risk (RRs) of diabetes was similar for participants with MetS (1.09 (95% CI 0.92, 1.29)). The age-adjusted relative risk of diabetes among those with impaired glucose tolerance (IGT) and MetS was 1.89 (95% CI 1.47, 2.42) and among those with IGT but without MetS was 1.59 (95% CI 1.32, 1.91). Areas under the receiver operating characteristic curves were 0.789 for fasting and 0.760 for 2-h glucose versus 0.595 for number of metabolic abnormalities (P<0.001).These data indicate that fasting or 2-h glucose during the OGTT may be more effective and efficient than MetS in predicting progression to diabetes.