Two ependymomas in adults, extending into both lateral ventricles have been reported. The final diagnosis was achieved by cranial computed tomography. This was particularly important in the first case while the clinical course and the previous diagnostic methods as angiography and isotope scintigraphy were misleading, suggesting a demyelinating process. This patient died because of a rare complication: intraoperatively evolved extradural, frontobasal hematoma which diagnosed again by CT-scan, but the removal of the hematoma was not performed on due time. In the second case a similar, but larger tumor could be removed successfully after CT diagnosis. The importance of CT-scan in diagnosis and operative decision of intraventricular tumors was emphasized.