The prevalence of overweight has increased over the past 10 years from 7.2% to 10.5% in 2-5 year old youth. Fifty-two % of children 3-5 years of age with BMI >95th percentile are obese as adults. Moreover the risk for a child to become an obese adult increases from 24% if neither parent is obese to 62% if one parent is obese. The 2-5 year old child is largely under parental control with parents modeling eating and activity habits and shaping the shared home environment. Despite the alarming increase in prevalence of pediatric overweight, there are no empirically validated treatments demonstrating efficacy in young overweight children and in primary care. The goal of this study is to test in primary care the efficacy of an innovative Family-based Intervention program for children aged 2-5 years with BMI >85th percentile and one obese parent. We hypothesize that the Intervention will lead to the child's weight loss/maintenance with reduction in % BMI overweight, and to parental weight loss. We are proposing to adapt our well-validated childhood weight control program developed in a specialized setting to be delivered in three large pediatric practices where the child is receiving his/her primary care. In this prospective randomized controlled 24-month study (12 month intervention and 12 month maintenance), 108 children (36/practice) with a BMI > 85th percentile and a parent with BMI >30 Kg/m2 will be assigned in equal numbers to an Intervention or Information Control group. The Intervention group will target both the child and the obese parent for weight control, dietary, activity and behavioral changes. The parent in the Intervention group will receive extensive teaching on behavioral modification methods leading to healthy habits (self-monitoring, praising, rewarding, contingency management, modeling, stimulus control). The Information Control group will focus only on child's weight control and the parent will receive only education relative to the child's dietary intake and activity. The pediatricians in the practice will play a key role in the identification and follow-up of study participants throughout the program. This study is an important step towards translating empirically validated treatments to usual practice and providing pediatricians with effective tools that may be used to treat obesity in clinical practice. Project Narrative This project addresses the problem of overweight in young children. We propose to treat concurrently overweight children and their parents in a family-based behavioral intervention program to be delivered in primary care. This study is an important step towards providing pediatricians with effective tools to treat overweight in primary care.