In recent years, some researchers have proposed that the depth of the mandibular antegonial notch can be used as a predictor of facial growth. However, the data for those studies were derived from populations with extreme morphologic characteristics. The purpose of this investigation was to test the hypothesis that the antegonial notch depth is a useful predictor of facial growth in a longitudinal sample of untreated growing patients selected at random. Lateral cephalometric radiographs were obtained from 20 males and 20 females at 3 times, approximating prepubescence (8.5 years), adolescence (12 years), and adulthood (> or = 17 years). These 40 subjects were randomly chosen from a longitudinal sample of untreated growing patients. Prepubescent and adolescent antegonial notch depths were correlated with vertical and horizontal growth changes of the jaws from the age of 8.5 years to adulthood. Correlation analysis revealed a statistically (but not clinically) significant negative relationship (0.40 < or = r < or = 0.47; P < or =.05) between adolescent antegonial notch depth and horizontal growth of the maxilla and the mandible from adolescence to adulthood. Previous investigators have proposed that antegonial notch depth, when extreme in magnitude, might be used to predict facial growth. We concluded that antegonial notch depth fails to provide sufficient indication of future facial growth to warrant its application as a growth predictor in a nonextreme population.