Twenty-six bronchial brush biopsies were performed in 21 patients with Hodgkin's disease. In most, brush biopsy was performed to differentiate between tumor, infection or the effects of radiation. In 17 bronchial brushings where Hodgkin's disease was subsequently shown to involve the lung, diagnosis of tumor was made in only four brush biopsies. In the remaining 13 patients, bronchial brushing failed to demonstrate tumor, sometimes on more than one occasion. In four patients who were subsequently shown to have pulmonary infections, bronchial brushings were of no value. Brush biopsy failed to diagnose a coccldioidomycetal lesion In one patient and a Pneumocystis carinii pneumonitis in another patient. Because of the low yield of diagnostic material in tumor (23 percent) and the questionable value of bronchial brushing in the diagnosis of infection, open lung biopsy may subsequently be necessary to establish the nature of a pulmonary lesion in Hodgkin's disease. However, the morbidity, mortality and cost compare so favorably with open lung biopsy that bronchial brushing and biopsy can be justified as an initial diagnostic procedure.