A two-step interview study of eating disorders (EDs) and sub-clinical EDs in 15-year-old adolescents was carried out in western Finland. The sample consisted of all ninth graders in a well-defined catchment area (n=606, 98.2% of eligible students). In the first step, a self-report questionnaire was administered at schools regarding mental health problems and life circumstances. The questions concerning anorectic and bulimic eating pathology were formulated according to the DSM-IV diagnostic criteria of EDs. The second step consisted of a semi-structured interview Rating of Anorexia and Bulimia-Teenager version (RAB-T) to which 128 subjects were invited, on the basis of their answers to questions about eating pathology in the questionnaire. The participation rate in the interview was 88.3%. The lifetime prevalence rate for anorexia nervosa (AN) in 15-year-old girls was 1.8% and the point prevalence rate 0.7%. No cases of AN were found among the boys. All criteria fulfilling cases of bulimia nervosa (BN) were not found in our sample. High rates of AN not otherwise specified (AN-NOS; 4.9%) and sub-clinical EDs (4.9%) were found among the girls; 6.7% of girls and 0.6% of boys were regarded as being "at risk" of developing EDs. Data on height and weight are based on current measurements taken at school healthcare; 22% of boys were overweight or obese compared with 16% of girls.