Depression among children and adolescents is common but frequently unrecognized. It affects 2 percent of prepubertal children and 5 to 8 percent of adolescents. The clinical spectrum of the disease can range from simple sadness to a major depressive or bipolar disorder. Risk factors include a family history of depression and poor school performance. Evaluation should include a complete medical assessment to rule out underlying medical causes. A structured clinical interview and various rating scales such as the Pediatric Symptom Checklist are helpful in determining whether a child or adolescent is depressed. Evidence-based treatment guidelines from the literature are limited. Psychotherapy appears to be useful in most children and adolescents with mild to moderate depression. Tricyclic antidepressants and selective serotonin reuptake inhibitors are medical therapies that have been studied on a limited basis. The latter agents are better tolerated but not necessarily more efficacious. Because the risk of school failure and suicide is quite high in depressed children and adolescents, prompt referral or close collaboration with a mental health professional is often necessary.