Chronic subdural hematoma is subject to post-operative fatal and non-fatal complications in 5 to 10% of the cases. Mortality ranges from 0 to 8%, depending on the preoperative clinical status. There is an average recurrence in 8% of the cases, chiefly linked to the absence of drainage. Empyema occurs in 2% of patients, especially when the drain is left in place more than 3 days. In most of the series, long-term epilepsy is a rare complication and patients do not require antiepileptic drugs. The lack of cortical reexpansion, postoperative intracerebral hematoma and tension hydrocephalus are, among others, complications occurring after surgery. Finally, 10% of the patients will have a permanent neurological impairment.