In France, as in all industrialized countries, the prevalence of overweight and obesity continues to rise among adults, children, and adolescents alike. Childhood overweight and obesity often persist into adulthood and are associated with increased risks of morbidity and mortality among individuals who were overweight during adolescence, even among those who return to a normal weight as adults. The school health service in the Haute-Savoie department, aware of the problem of overweight among children and adolescents, sought to assess the nutritional status of adolescents in its department and identify factors associated with overweight in order to implement targeted prevention and health education initiatives. A cross-sectional nutritional survey was conducted in September 2003 on a representative sample of 6th-grade students in public middle schools in Haute-Savoie. A stratification based on whether the school was located in a priority education zone (ZEP) or not was used. A cluster survey was then conducted in each stratum, interviewing all students in the randomly selected classes. 963 sixth-grade students in public middle schools in Haute-Savoie participated in the survey. According to International Obesity Task Force guidelines, the prevalence of overweight (including obesity) was 15.7%, of which 13.6% were moderately overweight and 2.1% were obese. The prevalence of overweight did not differ by gender or educational zone. The Haute-Savoie department therefore does not appear to be spared from the phenomenon of childhood overweight and obesity. While the observed prevalence of overweight is identical to the national prevalence, the problem of overweight nevertheless affects one in six children enrolled in 6th grade in public middle schools in this department, or approximately 1,185 children for the 2003–2004 school year. Children’s weight status at ages 11–12 appears closely linked to their weight status at ages 5–7; however, being overweight at that age does not account for all cases of overweight found in 6th grade. The prevalence of overweight status between ages 6 and 11 increases by 25%. Other factors are therefore associated with the development of overweight status at this age, particularly overly sedentary lifestyles and the establishment of eating habits. Survey biases must be taken into account when interpreting the identified associated factors. Thus, the conditions under which this survey was conducted may have led to recall and information biases. In particular, overweight children may have concealed their eating habits due to feelings of guilt. (R.A.)