A study of 95 patients with gliomas has been made. The 50% survival was 15 months after the first symptom. At the time of presentation all patients had an abnormal brain scan and E.E.G. except some of those who presented with epilepsy. The patients with epilepsy had a significantly better prognosis than those without and this was not due to their having less malignant tumours according to histological appearance. Other factors which were associated with significantly longer survival were a younger age at presentation, partial removal of the tumour rather than biopsy or no operation, lower histological grades of tumour and treatment with radiotherapy or chemotherapy.