Perinatal and medical information, growth, and the social background of 258 children who, in a prospective study, had superior intelligence at 7 years of age were reviewed. The subjects were divided into three categories on the basis of the results of psychological evaluation at age 7. Comparisons were made between those with superior (intelligence quotient greater than or equal to 120), average (IQ between 80 and 119), and low intelligence (IQ less than or equal to 79). A favorable parental social and educational background was the best correlate of superior intelligence in the children. Larger head size from 1 year of age was an early finding associated with superior intelligence. Greater height and weight, from 4 years of age were later findings. Correlations between psychological performance at ages 4 and 7 years were statistically significant. Perinatal factors and medical complications did not affect the intellectual status of children with superior intelligence.