We did a prospective study of 70 adults with chronic subdural hematomas. We looked at the correlation between some aetiological, clinical, and radiological factors and outcome. The present analysis found a significant positive correlation of cephalea, isodense aspect of the hematoma at CT scan, and pulsatance of the encephalon at surgery to good clinical outcome. Viceversa, alcoholism and intracranial hypotension associated with postoperative pneumocephalus are factors usually correlated with a negative clinical course.