The primary mucosa-associated lymphoid tissue(MALT) lymphoma of the lung is a rare low grade B cell lymphoma arising from bronchus-associated lymphoid tissue(BALT) which had been regarded as pseudolymphoma. It has the characteristic histologic with monoclonal B cells of centrocyte-like lymphoid cells and a lymphoepithelial lesion. Clinically it shows an indolent clinical course course and much more favorable prognosis than lymphoma of other site. We report 3 cases of the pulmonary malignant lymphoma of BALT, which was confirmed by lung biopsy, immunohistochemistry and PCR assay.