Objective: The aim was to investigate whether a computer-based evaluative conditioning intervention improves body image in adolescents with an eating disorder. Positive effects were found in earlier studies in healthy female students in a laboratory and a field setting. This study is the first to test evaluative conditioning in a clinical sample under less controlled circumstances. Method: Fifty-one adolescent girls with an eating disorder and a healthy weight were randomly assigned to an experimental condition or a placebo-control condition. The computerized intervention consisted of six online training sessions of 5 min, in which participants had to click on pictures of their own and other people’s bodies. Their own pictures were systematically followed by portraits of friendly smiling faces. In the control condition, participants were shown the same stimuli, but here, a stimulus was always followed by another stimulus from the same category, so that own body was not paired with smiling faces. Before, directly after, three weeks after, and 11 weeks after the intervention, self-report measures of body image and general self-esteem were administered. Automatic self-associations were also measured with an Implicit Association Test. Results:In contrast to our hypotheses, we did not find an effect of the intervention on self-report questionnaires measuring body satisfaction, weight and shape concern, and general self-esteem. In addition, the intervention did not show positive effects on implicit associations regarding self-attractiveness. Conclusions: These findings do not support the use of evaluative conditioning in its present form as an intervention for adolescents in clinical practice.