Low-grade bronchus-associated lymphoid tissue (BALT) lymphoma is a rare tumour originating from the marginal zone of lymphoid tissue. It is a subgroup of B-cell extranodal non-Hodgkin's lymphoma with an indolent course. We report a case of this tumour with characteristic histologic feature. The patient had non-specific respiratory complaints. The tumour occluded the right bronchus intermedius. He received radiation therapy alone, resulting in complete remission of the tumour and disappearance of symptoms.