A retrospective study of 152 cases of lymphomatoid granulomatosis (LYG) was undertaken to expand current knowledge about clinical manifestations and therapy, and to identify prognostic indicators in this disease. The major clinical and radiographic features and extra-pulmonary sites of involvement noted in previous studies were essentially confirmed in our study. Adverse prognostic factors included neurologic manifestations, and large numbers of atypical lymphoreticular cells within the pulmonary infiltrate. Unilateral chest lesions and large numbers of small lymphocytes and histiocytes within the infiltrate were associated with a better prognosis. Malignant lymphoma involving lymph nodes developed in 12% of patients. Almost two-thirds of patients have died and the median survival was only 14 months. No particular mode of therapy was found to be satisfactory for LYG, although there was some suggestion that corticosteroids may be useful. Randomized prospective studies are necessary for definitive recommendations regarding therapy.