Objective: Evidence on the validity of parental recall of early childhood behavior is lacking. Our aim was to examine the validity of parental recall at child age 10-12 years for maternal lifestyle during pregnancy, the birth characteristics, and early childhood behavior. Study Design and Setting: The study population comprised 2,230 children and their parents. Children aged 10-12 years were recruited from elementary schools (response: 76.0%). Parents were asked to recall lifestyle during pregnancy, birth characteristics, and childhood behavior at age 4-6 years. Recalled data were compared with information registered by Preventive Child Healthcare (PCH) from birth onwards. Results: For birth weight and gestational age, we found no systematic difference between recalled and PCH-registered data; 95% limits of agreement were +/- 1.2 pounds (600 g) and +/- 2.4 weeks, respectively. For maternal alcohol use during pregnancy and early childhood behavior problems, Cohen's kappas were low (0.03-0.11). Compared with PCH registration, parents tended to overreport at age 10-12 years. In contrast, kappa was high for maternal smoking during pregnancy (0.77). Conclusion: Retrospectively collected information on lifestyle during pregnancy, birth, and early childhood behavior is sometimes biased, which limits its value in estimating the contribution of early-life adversity to health in later life. (C) 2010 Elsevier Inc. All rights reserved.