Child and adolescent major depressive disorders are common and recurrent disorders. The prevalence of major depressive disorders is estimated to be approximately 2% in children and 4 to 8% in adolescents. Major depressive disorders in children are frequently accompanied by other psychiatric disorders, poor psychosocial outcome and a high risk of suicide and substance abuse, indicating the need for effective treatment and prevention. The use of antidepressant medications as the first line of treatment for children and adolescents with mild to moderate major depressive disorders has been questioned. However, some subgroups of patients may benefit from initial treatment with antidepressants. These subgroups may include patients who are unwilling or unable to undergo psychotherapy, have not responded to at least 8 to 12 sessions of psychotherapy, have bipolar, atypical or severe depression or have recurrent depression. Currently, the selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors are the first medication choice because of their efficacy, benign adverse effect profile, ease of use and low risk of death following an overdose. Further research in continuation and maintenance treatments, treatment of comorbid conditions, subtypes of depression, e.g. bipolar, atypical, seasonal, and combinations of pharmacotherapy and psychotherapy are needed. In addition, studies of the pharmacokinetics, pharmacodynamics and long term adverse effects of antidepressant medications in children and adolescents are warranted.