In this study, we review the parafine blocks of tumors of patients which previously graded as astrocytoma (18 patients), anaplastic astrocytoma (23 patients), glioblastoma multiforme (25 patients) and gliosis (6 patients). We used nucleolar organizer region associated protein (Ag-NOR protein) technique and the valves counted with light microscope. Mean valve of Ag-NOR counting as follows, 1.49'in gliosis, 2.93 in astrocytoma, 5.75 in anaplastic astrocytoma, 7.97 in glioblastoma multiforme. There were statistically differences between the groups (p = 0,001). We advice using Ag-NOR tecnique in the grading of astrocytomas.