Background and aims: The aim of this study was to investigate overweight and obesity among a representative population of 11,629 Turkish children aged 2-15 years and to elucidate the associations with different nutritional and socio-economic risk factors. Methods: In this cross-sectional study overweight and obese were defined using international age- and sex-specific cut-off points for body mass index. Data on basic characteristics, anthropometric measurements, family history of obesity, socio-economic status, dietary assessment and physical activity were collected. Results: The prevalence of obesity and overweight was 6.29% and 9.90%, respectively. A predominance of the obesity among boys in all age groups was observed (p<0.05), however no significant difference was found in overweight prevalence between genders at any age (p>0.05). The highest prevalence of obesity was found in children aged between 7 and 10 years. Logistic regression revealed that family history of obesity, lower educational levels of parents and poor family economy were significantly associated with overweight and obesity So were eating "unhealthy diet" and skipping breakfast. Physical activity and short duration in front of TV/PC were positively associated with not being obese and overweight. Conclusions: The prevalence of obesity and overweight in Turkish children aged 2-15 years was lower than in western and southern, but similar to central and eastern European countries. Overweight and obesity were associated with socio-economic factors and with factors related to food habits and nutrition, suggesting important areas for prevention. Obesity and Metabolism 2009; 5: 99-106.