Objectives.—To determine the suitability of the Migraine Disability Assessment (MIDAS) Questionnaire for assessing disability in children and adolescents with headache and to obtain preliminary information about disability in different primary headaches. Background.—During the last decade, researchers have begun to employ standardized methodologies to investigate the global impact of primary headaches. Disease-specific instruments have been developed to measure headache-related disability. The MIDAS Questionnaire, which is the most extensively studied of these instruments, was designed to assess the overall impact of headaches over the 3 months before compilation. The MIDAS Questionnaire is an optimal tool to assess headache-related disability in adults. Methods.—Ninety-five patients aged 7 to 17 years with tension-type headache, migraine, or both completed the validated Italian form of the MIDAS questionnaire on 2 occasions. Test-retest reliability was assessed by the Spearman rank correlation test. The Cronbach α assessed internal consistency. The patients answered questions about the adequacy of the questionnaire. Results.—The Cronbach α was .8. Correlation coefficients were generally high for the overall MIDAS score and for the items investigating disability in school and in family/leisure activities; they were lower for the items about housework. Most patients thought that the MIDAS Questionnaire was useful (98.9%) and that it captured the impact of their headaches (58.9%); 41% thought that questions about disability in housework were useless, 44.2% suggested adding questions regarding inability to do homework. All primary headaches had a considerable impact on daily activities, but patients with migraine tended to have lower headache frequencies and lower total disability time; those with tension-type headache suffered more days in which activities, although performed, were substantially impaired. Conclusions.—The MIDAS Questionnaire is useful for assessing disability in children and adolescents with different primary headaches. Minimal changes in the phrasing and content of the items would be sufficient to render the MIDAS specific for the younger population with headache.