Objective To study the characteristics of Ag NORs in the peripheral blood T lymphocytes (PBL) of patients with intracranial tumors. Methods Ag NORs in PBL was detected by a cell image analysis of KL 2 in 40 normal volunteers and 79 patients(intracranial benign tumor group, 27 patients;intracranial malignant tumor group, 20; other malignant tumors group, 32). Results Ag NORs in the intracranial benign tumor group was (6.42%?0.16)%, lower than (7.87%?0.10)% in the normal group that ( P