Ependymomas account for 2% of all intracranial tumors in adults. Considerable controversy continues to exist with regard to their prognostic factors and therapeutic management due to the rarity and the heterogeneity of series reported so far. The authors report a retrospective study of a homogenous population of 114 adult patients harboring WHO grade II intracranial ependymomas from 32 French Neurosurgical Centers between 1990 and 2004. All clinico-radiological and follow-up data were analyzed, and a central pathologic review was performed by two confirmed neuropathologists. The 5- and 10-year overall survival (OS) rates were 86.1% and 81.0%, respectively; the 5- and 10-year progression-free survival (PFS) rates were 74.6% and 58.9%, respectively. On multivariate analysis, the OS rates were associated with preoperative KPS score (P = .027), extent of surgery (P = .008), and tumor location (supratentorial vs infratentorial, P = .012). The multivariate analysis also revealed that the risk of recurrence was associated with incomplete resection (P = .001) and supratentotrial location (P = .038). Moreover, adjuvant radiotherapy (RT) for patients with incompletely resected tumors is responsible for a significant improvement of both overall (P = .005) and progression-free (P = .002) survival. This study clearly supports the major prognostic impact of the extent of surgery in WHO grade II. Interestingly, tumor location also seems to have an actual impact on both OS and PFS. Finally, the prognostic impact of RT was found to be beneficial for incompletely resected tumors.