Between April 1992 and February 1996, 97 patients with skull base meningiomas were treated at our department. The age of these patients ranged from 10 to 80 years. The male/female ratio was 1/2. Fifty-three of these patients had primary open surgery for partial removal or recurrent growth and subsequent radiosurgical treatment. Radiosurgery was performed as a primary treatment in 44 patients. The mean tumor volume was 13.7 cm3 (range: 0.8-82 cm3). These tumor volumes could be covered by mean isodose volumes of 45% (range: 20-70%) and were treated by a mean dose of 13.8 Gy (range: 7-25 Gy) at the tumor border. Six patients underwent radiosurgery with a staged treatment protocol with 4.6-6 months interval. In 78 patients, a total of 102 follow-up scans were available. The remaining 19 patients have not been included in the post-radiosurgical evaluation since the observation time was either too short or the patients were lost for follow-up. The mean interval between gamma knife treatment and last follow-up scan was 18.5 months, with a range from 6 to 46 months. Follow-up imaging (CT, MRI or both) revealed a decreased volume of the tumor in 31 cases (40%). In 44 cases (56%), tumor progression was stopped, and in 3 cases (4%) increased tumor volumes could be observed. In 8 cases marked central tumor necrosis was seen. Neurological follow-up examinations in 76 patients showed a stable neurological status in 71%, ameliorated status in 24% and worsening in 5% of the patients.