Background The purpose of this study was to examine the association between the change of parental weight status and the change of their child's weight status over 2 years. Methods: A total of 379 children ages 11-13 years were measured their height and weight in 2001 and 2003. Their parents completed a questionnaire including self-reported parental weight and height during the same period. Parental weight status was classified as overweight (BMI≥25 kg/m2) and non-overweight (BMI<25 kg/m2). Children's weight status was classified as overweight and non-overweight using the age and gender-specific BMI established by the Korean Academy of Pediatrics. The weight status over 2 years was categorized as a group of persistent overweight, persistent non-overweight, shifting overweight to non-overweight, and shifting non-overweight to overweight. Results: After adjusting for the child's gender and the father's weight status, the odds ratio for being persistently overweight over 2 years in a child having a mother with persistent overweight was 2.8 (95% CI: 0.9-8.5) compared to a child having a mother with persistent non-overweight. Likewise, the odds ratio for being persistently overweight over 2 years in a child having a father with persistent overweight was 2.9 (95% CI: 1.4-6.1) compared to the child having a father with persistent non-overweight. Conclusion: Parental weight status over 2 years was associated with the 2-year weight status in children. The parents- and family-based intervention are needed to prevent and manage childhood obesity. (J Korean Acad Fam Med 2008;29:336-341)