Major depressive disorder in children is a severe and a chronically disabling disorder. This population appears to be a special group in terms of consequences of poor psychosocial and academic outcome and increased risk of substance abuse, and suicide. Studies have revealed several major findings in genetic, familial, psychological, and biological aspects of such depression, some of which have explored into the issue of its relationship with adult depression. Considerable advances have been made now in the area of childhood depression providing a better understanding of its nature. We review literature available on historical aspect, epidemiology, clinical characteristics, and aetiology of childhood depression.