Depression is a common, chronic and recurrent disorder in children and adolescents. This article reviewed the epidemiology, clinical characteristics, natural course and treatment (pharmacological and psychotherapeutic treatment) of major depressive disorder (MDD) in children and adolescents. Several randomized controlled trials have shown that the selective serotonin reuptake inhibitors (SSRIs), in particular fluoxetine, and psychotherapeutic treatments such as cognitive behavioral therapy and interpersonal therapy are efficacious in children and adolescents with MDD. However, in Japan only three SSRIs (fluvoxamine, paroxetine and sertraline) are currently available, and few clinicians are trained to deliver psychotherapeutic treatment. Further clinical researches on the treatment to children and adolescents with MDD are needed in Japan.