Extrinsic allergic alveolitis (EEA) is a lung disease mediated by immunologic mechanisms and induced by repeated exposure to organic dusts. EAA in children are mostly observed around 10 years of age. Subacute clinical presentation is the most frequent. Diagnosis is based on simultaneous presence of most of the following arguments: exposure to a known risk factor, spontaneous improvement after cessation of the exposure, identification of specific precipitins, demonstrative aspects on X-ray and tomodensitometry, and CD8+ lymphocytosis in bronchoalveolar lavage. Lung biopsy and specific provocation test are rarely necessary for diagnosis. Treatment is based on total eviction from inhaled antigen and on oral corticosteroids in acute and subacute forms.