Within the criminological literature, examinations of the link between cognitive ability and crime have had a dubious history. Part of the problem, the authors contend, is that IQ tests have been relied on as a measure of cognitive ability, when in fact IQ scores may not accurately reflect the cognitive abilities of those taking the tests, especially populations from disadvantaged backgrounds. As such, the authors re-visit possible correlations between cognitive ability and delinquent behavior through an examination of youths’ performance on the California Achievement Test (CAT). Drawing from the life-course perspective, the authors examine the effect of cognitive ability on three measures of delinquency: onset of offending, early onset of offending, and persistence of offending. The dataset that was used was obtained from the Inter-University Consortium for Political and Social Research and involved the analysis of the Longitudinal Study of Biosocial Factors Related to Crime and Delinquency in Pennsylvania. Data from 987 youths reveal that cognitive ability maintains a significant inverse relationship with the likelihood of the onset of delinquency, the early onset of delinquency, and the persistence of delinquency. The authors contend that although the results do not indicate that cognitive ability is a substantively important predictor of delinquent behavior, it does reveal that cognitive ability is an important risk factor that should be considered in the development of intervention strategies aimed at inner-city youth. Implications are noted for the continued development of structural and multilevel theories of crime and delinquency. Tables, notes, references