Examination of 500 premature and 492 full-term infants at 40 weeks of age indicated that there is a continuum of cerebral damage ranging from severe abnormalities, such as cerebral palsy and mental deficiency, to minimal damage. All degrees of involvement increased as the birth weight decreased. The number and severity of abnormal neurological and behavior patterns recorded varied directly with the severity of the clinical neurological diagnosis. The component items for a diagnosis of minimal cerebral damage in infancy are described. Findings of adaptive functioning at 40 weeks were found to be well correlated with maturity levels at 3 years of age and therefore have predictive value. Behavior problems in children have been ascribed to tension in their mothers, but the likelihood that an infant with difficulties produces tension in his mother needs serious consideration.