A 57-year old man with desquamative interstitial pneumonia (DIP) showed a marked increase in eosinophils in the bronchoalveolar lavage (BAL) fluid. The patient was referred to our hospital for abnormal shadows on his chest X-ray with no symptoms in May 2007. Computed tomography (CT) showed patchy, peripheral predominate ground-glass opacity. The BAL fluid revealed an increase of the total number of cells, including markedly elevated levels of eosinophils (62.1%), in contrast with only a slight increase of peripheral blood eosinophils, or minimal eosinophils in the alveolar spaces and interstitium of the thoracoscopic lung biopsy specimen. Since the specimens showed findings compatible with a DIP pattern, we diagnosed the patient with DIP. Although it is a rare entity, we should therefore consider DIP in the differential diagnosis when we encounter patients with a marked increase in the number of BAL eosinophils.