Diffuse idiopathic pneumonia with alveolar filling gather disorders whose clinical and radiological aspects are varied. It is important to precisely identify them because of the prognostic and therapeutic implications suitable for each one of them. Among these, it is necessary to distinguish the eosinophilic pneumonias, wether acute or chronic, which are characterized by circulating and (or) alveolar hypereosinophilies; the diffuse alveolar haemorrhages whose potential severity requires an early recognition in order to institute a treatment without delay; the pulmonary alveolar phospholipoproteinosis can be easily evoked because of their particular radiological features, associated with a lactescent aspect of bronchoalveolar lavage. Lastly, bronchiolo-alveolar carcinoma and more exceptionally the pulmonary alveolar microlithiasis must be considered.