The stability of indicators of the metabolic syndrome from childhood and adolescence to young adulthood was examined. The sample included 76 males and 71 females measured between the ages of 8 and 18 years and again as young adults (12 year follow-up). Indicators included the sum of three trunk skinfolds (SF3), mean blood pressure (MBP), and fasting blood glucose (GLY), high-density lipoprotein cholesterol (HDL-C), ratio of total cholesterol to HDL-C (CHOL/HDL), and triglycerides (TG). The indicators were subjected to principal components analysis to obtain a composite risk factor index (RFI). Partial interage correlations, controlling for initial age and length of follow-up, were 0.70 and 0.50 for SF3, 0.40 and 0.54 for MBP, 0.58 and 0.56 for HDL-C, 0.51 and 0.57 for CHOL/HDL, 0.37 and 0.20 (NS) for TG, 0.30 and 0.14 (NS) for GLY, and 0.51 and 0.46 for the RFI, in males and females, respectively. The results indicate that indicators of the metabolic syndrome are moderately stable from childhood and adolescence into young adulthood.