Malignant lymphoma arising from mucosa-associated lymphoid tissue (MALT) represents distinct clinicopathologic features and remains localized for prolonged periods. We report a case of low grade B cell lymphoma of bronchus-associated lymphoid tissue (BALT). A 60-year-old female had a long-standing cough, sputum and intermittent fever for 10 years. In 1984, the chest radiography showed increased hazy density in both upper lungs. Although she had been treated by antituberculous medication under clinical diagnosis, there was no improvement. In 1995, open lung biopsy was carried out. Histologically, it showed massive nodular or diffuse infiltration of centrocyte-like cells in bronchus and parenchyme with pleural invasion. On immunohistochemical stain, they were positive for LN-2 and L26 and negative for UCHL-1, LN-1 and LN-3. In polymerase chain reaction (PCR), Ig heavy chain gene rearrangement was detected. The patient was well for 6 months after the biopsy.