Objective: : Chronic subdural hematoma (CSDH) is one of the most common pathology in daily neurosurgical practice and incidence increases with age. The aim of this study was to evaluate the prognostic factors and surgical outcome of CSDH in patients aging over 90 years compared with a control group of patients aging under 90 years. Methods: : This study reviewed 25 patients with CSDH aged over 90 years of age treated in our department. This group was compared with a younger group of 25 patients aged below their eighties. At admission past medical history was recorded concerning comorbidities (hypertension, dementia, ictus cerebri, diabetes, and heart failure or attack). History of alcohol abuse, anticoagulant and antiplatelet therapy, head trauma and seizures were analyzed. Standard neurological examination and Markwalder score at admission, 48 hours after surgery and 1–6 months follow-up, radiologic data including location and CSDH maximum thickness were also evaluated. Results: : Their mean age was 92.8 years and the median was 92.4 years (range, 90–100 years). In older group, the Markwalder evaluation at one month documented the complete recovery of 24 patients out of 25 without statistical difference with the younger group. This data was confirmed at 6-month follow-up. One patient died from cardiovascular failure 20 days after surgery. The presence of comorbidities, risk factors (antiplatelet therapy, anticoagulant therapy, history of alcohol abuse, and head trauma), preoperative symptoms, mono or bilateral CSDH, maximum thickness of hematoma, surgical time and recurrence were similar and statistically not significant in both groups. Conclusion : In this study, we demonstrate that surgery for very old patients above 90 years of age affected by CSDH is safe and allows complete recovery. Comparing two groups of patients above and under 90 years old we found that complication rate and recovery were similar in both groups.