The aim of the present study was to investigate the prevalence of eating disorder (ED) traits among obese children and adolescents. The Swedish version of the Eating Disorder Inventory for Children, consisting of 11 subscales, was administered to 150 obese patients during an extensive investigation of causes and risk factors in obesity at the Karolinska University Hospital at Huddinge. Patients aged 17-18 years (N=24) had a mean body mass index (BMI) of 40.7, SD 5.31, and patients aged 8-16 (N=126) had a mean body mass index standard deviation score (BMI SDS) of 6.18, SD 1.69. These patients were compared with 201 girls with a diagnosed ED from the COEAT project and with a control group of schoolchildren. The comparison between obese girls and boys showed that adolescent obese girls scored higher than obese boys on Drive for Thinness, Bulimia and Body Dissatisfaction. They also scored higher on Ineffectiveness, Interoceptive Awareness and Impulse Regulation. Obese girls were close to the girls with an ED on six of the subscales. Obese boys had a lower score of Asceticism than boys in the control group. The conclusion is that psychological traits associated with disordered eating appear among obese patients, particularly among the girls. However, these patients rarely satisfy any diagnostic criteria for ED during childhood or adolescence. Since obesity treatment currently assumes rational behavior, i.e. no EDs, it is important to discover ED traits at an early age in order to adapt treatment accordingly.