In this paper, a case of nontraumatic subdural hematoma secondary to dural metastasis of lung cancer was presented and 43 cases in the literature were reviewed. A 75-year-old man who had been affected with lung tuberculosis for the previous 7 years was admitted to our hospital because of right hemiparesis and aphasia. No history of head injury was discovered. On admission, he was fully conscious and no other neurological abnormalities were noticed except for right hemiparesis and motor aphasia. The chest X-ray revealed abnormal shadows on the right lung, which were most suggestive of tuberculosis. Laboratory studies including prothrombin time, platelet count and fibrinogen were normal. The CT scans taken at that time demonstrated a large subdural hematoma over the left hemisphere. Under a diagnosis of chronic subdural hematoma, emergency evacuation through a small burr hole was performed. However, because of its low liquidity, the hematoma was insufficiently removed. Postoperatively, hemiparesis gradually disappeared. On the 20th hospital day, he suddenly became unconscious and CT scans showed recurrence of the subdural hematoma. Temporo-parietal craniotomy was immediately carried out. The dura was thickened and hyperemic. Although the underlying brain was apparently normal, the exploration performed after removal of the hematoma revealed a soft grayish mass extruding into the subdural space from the dura. The bleeding point was not identified. Both the dura and the abnormal tissue were biopsied for histological examination.(ABSTRACT TRUNCATED AT 250 WORDS)