700 children from 18 schools located in Athens were enrolled. 8.6% of boys and 9% of girls were obese, whereas 33.9% of boys and 22.1% of girls were overweight. For boys, the adjusted odds ratio for breakfast cereal intake for being overweight or obese was 0.54 (95% confidence interval (CI): 0.45-1.29), while for girls it was 0.41 (95% CI: 0.21-0.79). This study provides evidence that breakfast cereal as a most frequent choice, and daily consumption of breakfast, are inversely associated with the prevalence of overweight or obesity in 10-12-year-old children.