BALT(bronchial associated lymphoid tissue) lymphomas are a distinct subgroup of low-grade B-cell extranodal non-Hodgkin's lymphoma, which are classified as a marginal-zone lymphomas. The majority of the patients are asymptomatic or their pulmonary lesions is often discovered incidentally on a routine chest radiograph. A 50-year-old man was admitted for an the evaluation of cough, dyspnea and fever. His chest CT showed ground glass appearance with interlobular septal thickening in both lower lobes, right middle lobe and left lingular division. He had been initially diagnosed with lipoid pneumonia and was kept under observation. However, his chest lesion showed continuous progression and a video-associated thoracoscopy was performed His pulmonary lesion was confirmed histologically to be a BALT(bronchial associated lymphoid tissue) lymphoma. We report a case of a BALT lymphoma, which was initially misdiagnosed as lipoid pneumonia.