Among 18 patients with locally advanced malignant neoplasms of the head and neck region, bronchial washings failed to reveal tumor cells despite the demonstration of exfoliated tumor cells in washings from the region of the primary tumor in 13 (72%) of the patients. Among 17 patients with bronchogenic carcinomas, however, tumor cells were isolated from the bronchial washings in 14 (82%). These results indicate that, in patients with malignant neoplasms of the head and neck, tumor cells found in bronchial washings probably are not from the primary head and neck neoplasms. Thus, cytologic examination of bronchial washings may be validly employed in the differential diagnosis of the pulmonary tumors in patients with malignant neoplasms of the head and neck region.