The clinical significance of the "metopic fontanelle" was evaluated by the examination of 1,892 control infants (clinically normal) and 88 infants with some clinical abnormality, during the newborn period. A significantly increased incidence of the metopic fontanelle was found in infants with the congenital rubella syndrome, Down's syndrome, cleft lip with or without cleft palate, and widened sutures. It is not significantly increased in infants presenting with facial asymmetry with torticollis, and in a group comprising infants with various abnormalities; the numbers in each category of abnormality in this group were too few for direct comparison with the controls. The metopic fontanelle is easy to palpate, and the discovery of its presence might occasionally be helpful in the clinical examination of the newborn infant.