The argyrophilic method for the demonstration of nucleolar organizer region-associated proteins (AgNOR's) was applied to paraffin-embedded histologic sections of 30 meningiomas. These were divided into three groups: 1) group I comprising 10 primary tumors which subsequently recurred within five years; 2) group II including the relative recurrences of the above mentioned primary tumors; 3) group III consisting of 10 nonrecurrent tumors over a follow-up of at least five years. The means of AgNOR counts were 1.58 with a SD of 0.67 for the group I, 1.47 with a SD of 1.04 for the group II, and 1.42 with a SD of 0.62 for the group III. A statistical analysis of these data using the Student's "t" test showed no significant difference between primary tumors and relative recurrences, as well as between primary and nonrecurrent tumors. However, when the AgNOR number was > 2.0 there was a statistically significant difference between primary and nonrecurrent meningiomas. These results are discussed in light of the findings previously reported by the literature.