In this article, children's performance on subtasks from the Cambridge Neuropsychological Testing Automated Battery (CANTAB) is described. Two samples were recruited, one of which included children who spoke English as a second language. Children in this group also completed subtests from the Wechsler Intelligence Scale for Children-Third Revision (WISC-III). Despite the fact that ESL children scored over 1 SD below the norm on the WISC-III Vocabulary subtest, there were no CANTAB performance distinctions between primary versus secondary English-language speakers. In addition, several aspects of CANTAB performance were significantly correlated with verbal and nonverbal IQ. When developmental trends were examined, findings indicated that several aspects of frontal lobe function (memory span, working memory, and planning skills) are not functionally mature, by the age of 12 years. Implications for use of the CANTAB in clinical studies are discussed.