Obsessive compulsive disorder (OCD) involves obsessions and compulsions that cause impairment and distress, and which interfere with children's developmental adaptation, daily functioning. Further more, OCD often disrupts peer and family relationships and school performance. One considered rare, recent epidemiological studies report prevalence rates ranging from 1% in prepubertal children to 3% in adolescents. Recently, significant advances have been made in understanding of the aetiology, pathophysiology, phenomenology, and treatment in children. The ongoing refinement of cognitive-behaviour and pharmacological treatment approaches has increased the likelihood that many youngsters with OCD will lead satisfying and relatively normal lives.