Meningioma is often regarded as a benign tumour. It is easy to diagnose, but its prognosis is difficult to determine. Recurrences are numerous and occur at different periods of time. Various predictability factors have been studied, including Nucleolar Organizers Regions (NORs) staining. This technique is easy to perform and enables retrospective studies to be carried out. Comparisons of staining indices with the histoprognostic grades established by Zülch, and correlations between these indices, as well as with the time elapsed before a recurrence occurred, showed that NORs staining can be useful to determine the prognosis. In this retrospective study 69 cases were reviewed. The meningiomas had been removed surgically between January 1979 and December 1991. The clinical follow-up, which lasted from 11 months (for the most recent cases) to 132 months (for the earlier cases), shows that the staining index reaches a critical value beyond which an early recurrence might be expected.