Purpose: To describe trajectories of emotional and behavioral problems in adolescents and to identify early indicators of these trajectories using data from routine well-child assessments at ages 0-4 years. Methods: Data from three assessment waves of adolescents (n = 1,816) of the TRAILS were used (ages: 11-17 years). Information on early indicators (at ages 0-4 years) came from the records of the well-child services. Trajectories of emotional and behavioral problems were based on the parent-reported Child Behavior Checklist and the adolescent-reported Youth Self-Report, filled out at ages 11, 14, and 17 years. Multinomial logistic regression analysis was used to examine the predictive value of th Results: For boys and girls, we found four trajectories for each outcome: one with high problem levels, and three with middle-high, middle-low, and low levels. For emotional problems, the type of trajectory was predicted by parental educational level and parental divorce or single parents, for both genders. Moreover, sleep problems were predictive in boys and language problems in girls (odds ratios between 1.53 and 7.42). For behavioral problems, the type of trajectory was predicted by maternal Conclusions: Trajectories of emotional and behavioral problems during adolescence are rather stable and can be predicted by a parsimonious set of data from early well-child assessments. (C) 2012 Society for Adolescent Health and Medicine. All rights reserved.