Two cases of acute eosinophilic pneumonia (AEP) are described and the radiographic findings discussed. Two patients presented acute fever and cough, which led to acute respiratory insufficiency in 3 days. There was no past history of asthma, hypersensitivity or allergy. They became well within 5 to 12 days, with corticosteroid in one and spontaneously in another. Bronchoalveolar lavage showed more than 80% eosinophils. Plain chest roentgenogram showed air space consolidation with peripheral predominance in case 1 and ground-glass shadow with reticular pattern in case 2. On CT, dense and faint air-space opacities were noted in both entire lung fields in case 1 and faint opacities with thickened interlobular septa in case 2. Bilateral pleural effusion and mild mediastinal lymphadenopathy were noted in both. The increased lung densities showed non-segmental distribution. However, these findings are non-specific and such opacities are seen in other diffuse lung diseases such as hypersensitive pneumonitis, BOOP and pulmonary edema. Pleural effusion (44% of reported cases including ours) and mediastinal lymphadenopathy were frequently seen, and pleural effusion with or without mediastinal lymphadenopathy could represent specific findings for this disease. The authors stress that in young patients with acute respiratory insufficiency with pleural effusion and/or mediastinal lymphadenopathy on the plain chest radiograph or on CT, the possibility of AEP should be considered in the differential diagnosis.