OBJECTIVE This study was undertaken to determine the effects of repeated courses of antenatal corticosteroids on childhood behavior and disabilities, including cognitive delay and cerebral palsy. STUDY DESIGN Nonrandomized regional cohort of 541 very preterm infants born in Western Australia from singleton pregnancies and alive at 3 years were included in the study. MAIN OUTCOME MEASURES Physical, cognitive, and psychological assessments up to 6 years. RESULTS Increasing numbers of antenatal corticosteroid courses were associated with a reduction in the rate of cerebral palsy. Three or more courses were also associated with increased rates of aggressive/destructive, distractible, and hyperkinetic behavior and these effects were present at both ages 3 and 6 years. Measures of internalizing behavior and intelligence quotient were unaffected by antenatal corticosteroid use. CONCLUSION Repeated antenatal courses of corticosteroids may protect against cerebral palsy but are associated with hyperactivity later in childhood.