We examined 11-year (1997-2007) trends in underweight, overweight, and obesity in Greek children. Population data derived from a yearly, school-based health survey carried out between 1997 and 2007 in >80% of all Greek schools. Height and weight measurements from 651,582 children, aged 8-9 years (boys: 51.2%) were analyzed. The gender- and age-specific BMI cutoff points by the International Obesity Task Force (IOTF) were used in order to define underweight, normal weight, overweight, and obesity. Trend analysis showed an increase in the prevalence of obesity from 7.2 +/- 0.2% in 1997 to 11.3 +/- 0.2% in 2004 for girls (P < 0.001) and from 8.1 +/- 0.2% in 1997 to 12.3 +/- 0.2% in 2004 for boys (P < 0.001). An apparent leveling off in obesity rates was observed during 2004-2007 for both boys and girls. The prevalence of overweight rose between 1997 and 2007 from 20.2 +/- 0.2% to 26.7 +/- 0.2% for girls (P < 0.001) and from 19.6 +/- 0.2% to 26.5 +/- 0.2% for boys (P < 0.001). The overall prevalence of thinness in the same period remained constant in both sexes. The presented population-based data revealed that the prevalence of overweight and obesity among 8- to 9-year-old Greek children is alarmingly elevated, with the overweight rates rising continuously. However, an apparent leveling off in obesity rates for the past 4 consecutive years was documented for the first time in both genders.