The records of patients who had transbronchial lung biopsy at Walter Reed Army Medical Center between January 1974 and September 1977 were retrospectively reviewed. Nine patients were found whose clinical and radiographic presentations were compatible with lymphangitic carcinomatosis. In five patients the lymphangitic spread of carcinoma was diagnosed from transbronchial lung biopsy specimens. A single patient had a false-negative biopsy, proven at autopsy three weeks later. The other three patients with negative biopsies are alive and receiving chemotherapy 12 months later (two patients) or are lost to follow-up (one patient). Transbronchial lung biopsy is an accurate procedure for diagnosing lymphangitic carcinomatosis. In addition, aggressive chemotherapy should not be used in these patients without a tissue diagnosis.