The pattern of pulmonary infections in 59 consecutive bone marrow transplantations in Hong Kong was reviewed. Compared with published data from other marrow transplant units, we had a lower incidence of cytomegalovirus pneumonitis (1.7%) and a higher incidence of mycobacterial infections (5%). The latter is probably related to the high background prevalence of tuberculosis in the local population. Treatment with antituberculous drugs was effective.