Purpose: To assess the prevalence of DSM-IV anorexia nervosa criteria, anorexia nervosa and subthreshold subgroups, and their incidence between the ages of 12 and 17 years using Cole’s international thinness cut-offs, and to characterize these anorexic adolescents by parental socioeconomic status and whether or not they reported receiving treatment. Method: In all, a representative sample of 39,542 French adolescents (19,658 girls and 19,884 boys) was recruited in a cross-sectional study in 2008. Anorexia nervosa DSM-IV diagnosis was determined by a self-administered questionnaire. Results: Among females, 0.5% (n = 105) met criteria for anorexia nervosa between the ages of 12 and 17 years, whereas among males, the prevalence was 0.03% (n = 6). In females, the prevalence of sub-threshold anorexia nervosa was found to be between 1.2% (n = 216) and 3.3% (n = 618); more than 75% were of the restrictive subtype. The highest incidence of anorexia nervosa was at 16 years. There was also a greater prevalence of sub-threshold anorexia nervosa subgroups among subjects with high parental socioeconomic status. More than half of the female adolescents who met the anorexia nervosa criteria reported receiving treatment for their disorder, versus 23% to 40% of the adolescents in the sub-threshold subgroups (P < 0.0001). Conclusions: This study is the first to report the prevalence of AN on such a large community sample of adolescents. Using Cole’s international thiness cut-off could improve international comparability among studies. Adolescents from the higher socioeconomic categories were more likely to be anorexic.