Preventive therapy for migraine headache includes identification of migraine precipitants, possible adjustments in lifestyle, appropriate management of acute headache, and, when necessary, the use of pharmacologic agents. There are no well-controlled clinical trials with sufficient patient numbers to support the use of any agent in the prevention of migraine headache in children. Data on the use of amitriptyline and divalproex sodium in open-label studies suggest that these agents may be efficacious. The mechanism of action for these agents is unknown but may be related to the 5-hydroxytyptamine-2 (5-HT2) receptor antagonism or regulation of ion channels. A review of the pertinent literature on migraine prophylaxis in children is presented. Dosing guidelines are presented based on the limited data available and clinical experience.