Eosinophilic lung diseases encompass a broad range of conditions wherein patients present with pulmonary opacities and eosinophilia of the serum, pulmonary tissue, or bronchoalveolar lavage fluid. Many of these entities can be idiopathic or are secondary to parasitic infection, exposure to drugs, toxins, or radiation. These diseases exhibit a wide range of imaging findings, including consolidation, ground-glass opacities, nodules, and masses. Diagnoses often require bronchoalveolar lavage and/or biopsy to confirm respiratory eosinophilia and to exclude other entities, such as infection or malignancy. Treatment entails administration of corticosteroids, removal of inciting agents, and treatment of underlying infection.