Objective: To determine behavioural outcome at 3 years age in very premature infants in a regionally defined, prospective cohort study. Methods: The Epipage study includes all live born infants of <33 weeks gestational age, born in 1997 in nine regions of France and a control group of term infants; 2276 (96%) parents of premature infants discharged home and 557 parents (84%) of term infants agreed to a follow up. A postal questionnaire was answered at 3 years old for 1880 (83%) very preterm survivors and 453 (81%) term infants. Nonresponders did not differ from responders for neonatal morbidity of the child, but they were more often socially disadvantaged. Behaviour was assessed with the Strengths and Difficulties Behaviours Questionnaire. We include in this analysis 1228 singleton premature infants without severe neurodevelopment disabilities and 447 term infants. Results: On the behaviour questionnaire, the very premature infants showed significantly higher difficulties than term children: 20% versus 9% for total difficulties score, 20% versus 11% for hyperactivity score, 16% versus 10% for conduct problems score, 15% versus 10% for emotional symptoms score, 14% versus 7% for peer problems score, 15% versus 11% for pro social behaviour score. Boys had higher total difficulty and hyperactivity scores. A lower socioeconomic status was related to a higher frequency of behavioural problems, which was significant for total difficulty score, conduct problems score and pro social behaviour score. After controlling for gender, mothers age, and socioeconomic and marital status, most differences between very preterm and term children were still significant: for total difficulties (odds ratio (OR) 2.3; 95% confidence interval (CI) 1.6 to 3.3; p = 0.001), hyperactivity (OR 2.0; CI 1.4 to 2.8; p = 0.001); conduct problems (OR 1.7; CI 1.2 to 2.4, p = 0.006), emotional symptoms (OR 1.6; CI 1.1 to 2.4; p = 0.007); and peer problems (OR 1.9; CI 1.3 to 2.9; p = 0.002). These differences in behaviour persisted when additional controls were added for health or development of the child. Conclusion: The prevalence of behavioural problems assessed by parents at 3 years of very premature infants was higher than in term infants.