Childhood constipation is ofton a long_term problem requiring treatment over months or years. There is no single treatment metod for constipation and many children do not respond and continue to have chronic problems. Treatment is consisted of: Disimpaction,Drug adminstration , Diet modilation, and behaverial therapy. It is necessary in all cases that not responding to conventional therapy, un diagnosed organic causes, non proper drug, short course therapy, behaverial disorder and withholding should be considered. Internal anal achalasia, Neural tube defect, Neurointestinal dysplasia. and food allergy are the most important predisposing factors in treatment failer . PEG is drug of choice for treatment and therapy must be continued for several months or years. Psycologic consulting should be considered in patients with severe behaverial disorder. Key words: Children, Functional Constipation, Treatment.