Purpose: According to the developmental origins of health and disease theory, fetal nutrition is associated with obesity and chronic diseases in children and adults. However, previous findings regarding the association between birth weight and childhood obesity have been inconsistent. The aim of the present study was to investigate the relationship between birth weight and childhood obesity in China. Methods: The 16,580 subjects (8477 boys and 8103 girls) aged 7-17 years, who participated in this study were recruited from a cross-sectional study in six cities in China. Epidemiological data, including birth information, were collected through face-to-face interviews, and anthropometric indices were measured by trained physicians. Overweight and obese cases were defined using sex-specific and age-specific 85th and 95th percentile body mass index (BMI) cutoffs for Han children and adolescents. Central obesity was defined using sex-specific waist-to-height ratio (WHtR) cutoffs (WHtR >= 0.48 in boys and WHtR >= 0.46 for girls). Results: The overall rate of overweight status and obesity was 20.3% in the Chinese children and adolescents and that of central obesity was 18.9%. Subjects were stratified into eight groups according to weight at birth, j-shaped relationships were observed between birth weight and BMI for age Z-score and WHtR. After adjusting for confounders such as gender, gestational age, parental factors, and dietary factors, the risk of overweight and obese status was still higher in the children with higher birth weights than in children with birth weights of 3000-3499 g (3500-3999 g: odds ratio [OR] = 1.14, 95% confidence interval [CI] = 1.02-1.28; 4000-4499 g: OR = 1.39, 95% CI = 1.19-1.63; and 4500-4999 g: OR = 1.36, 95% CI = 1.06-1.76). Moderately high birth weight also increased the risk of central obesity. Relative to the children with normal birth weights (3000-3499 g), the adjusted OR and 95% CI were 1.33 (1.13-1.56) in children with birth weights of 4000-4499 g. Children with very low birth weight (lower than 1500 g) had the highest risk of central obesity. The adjusted OR was 2.30 (95% CI: 1.03-5.14) relative to children with birth weights of 3000-3499 g. Conclusions: Birth weight was associated with obesity in Chinese children and adolescents, j-shaped relationships were observed between birth weight and BMI and WHtR in childhood, and very low birth weight was associated with a mild increase in the risk of central obesity in Chinese children and adolescents. (C) 2015 Elsevier Inc. All rights reserved.