Depression is a common disorder among adolescents, often runs a chronic and relapsing clinical course. Many researches have showed that in the early 1990s there continued to be a Jack of empirical evidence supporting the use of specific treatments for adolescent depression. Therefore, there was an interest in developing and testing new treatments, particularly those that are short-term and manualized. IPT-A as a treatment approach that may beeasi1y disseminated to a variety of settings, emphasizing to identify the problem area, to relate depressive symptoms to problem areas, to focus on the current relation ships, and to help the patient master the interpersonal context of his or her depression have a crousial role. Thus, the main purpose of the present study was to study the effectiveness of interpersonal psychotherapy on adolescents' depression. Method of the present study is case study. One famale patients who met the DSM IVTR criteria for depression aged 16 years old was selected.Data was obtained by clinical interview and psychological assessments. The results suggest that IPT-A is an efficacious treatment for adolescent depression.