Objectives To assess antenatal and early postnatal antecedents of attention problems identified by the Child Behavior Checklist in extremely preterm children. Study design In a cohort of 826 children born between 23 and 27 weeks' gestation, we collected demographic, birth, and postnatal information. We then identified behavior problems by using parent ratings from the Child Behavior Checklist at 2 years' adjusted age. We created time-oriented logistic regression risk models to identify significant risk factors for attention problems and Diagnostic and Statistical Manual of Mental Disorders –compatible attention deficit/hyperactivity problems (ADHPDSM ). Results Children were at increased risk of both attention problems if they were born to a woman who had no formal education beyond high school and/or a woman who was exposed to secondhand smoke. Recovery of a single organism from the placenta was associated with increased risk of an attention problem, and fetal stem vessel thrombosis and recovery of Mycoplasma species were associated with increased risk of ADHPDSM . Infants of multifetal gestations were at reduced risk of both attention problems. The only postnatal risk factor for an attention problem was recovery of bacteria from a tracheal aspirate. Conclusion Among extremely preterm infants, several potentially modifiable antenatal and perinatal antecedents are associated with increased risk for attention problems and ADHPDSM at 2 years adjusted age.