ABSTRACTThis report pertains to the development of bronchogenic carcinoma in 4 elderly patients with chronic lymphatic leukemia. The abnormal radiologic shadows in the lung (confined to the upper lobes and hili) were noted 30–60 months after recognition of the hematologic abnormality. Spread to ipsilateral or contralateral lymph nodes was common. After the appearance of lung carcinoma, the patient's course was downhill, with an average survival period of 2 months. The development of a new pulmonary lesion in any patient with chronic lymphatic leukemia should arouse the suspicion of malignancy and lead to prompt investigatio