The prognostic significance of various histological features was examined in 161 patients with meningiomas in whom the tumour was thought to be completely removed at the time of operation. Undifferentiated malignant tumours were not included in the material. The histological classification used was that of Courville (1950). When the various histological types of meningiomas were compared, only a small subgroup of the angioblastic meningiomas was found to recur with significantly higher frequency than the others. These tumours has the appearance of “haemangiopericytomas”. Among the other types, the frequency of recurrence was almost the same. Differences were tested by an X2-test with correction for continuity. The prognostic significance of various other histological and cytological details was examined only in the syncytial group, which comprised 84 cases. High cellularity was found more frequently among the recurring tumours. This difference was statistically significant. There was also some preponderance of high vascularity, diffuse growth, mitoses, focal necroses and infiltration into bone and cortex among the recurrences. None of these differences were statistically significant. Nuclear pleomorphism occurred almost equally in both groups.