Meningiomas are the most common primary benign brain tumor. Radiosurgery (primary or adjuvant) allows excellent local control. The Geriatric scoring system (GSS) for pre-operative risk stratification and outcome prediction of patients with meningiomas has been previously reported. The GSS incorporates eight tumor and patient parameters on admission. A GSS score higher than 16 was previously reported to be associated with a more favorable outcome. We assessed the validity of the GSS score and its influence on outcome in patients treated with gamma-knife radiosurgery (GKRS). Methods: Patients treated with single session GKRS for WHO-1 meningioma during 1989-2013 at the University of Virginia were reviewed. A cohort of 323 patients, 50.2% (n=162) males. Median age was 56 (29-84), and median follow-up was 53.6 (6-235) months. Median tumor volume was 4.5 cm3 (0.2-23). Median margin and maximal doses were 15 Gy (8-36) and 32.3 Gy (20-65), respectively. Results: Tumor volume control was achieved in 87% (n=281), and post-GKRS clinical neurological improvement reported in 66.3% (n=214). The median change in KPS was +10 (range -30 to +40). The most common complication was intermittent headaches (34.1%, n=110) and cranial nerve deficits (14.2%, n=46). The GSS (calculated and grouped as GSS>16 and GSS<=16) was found to correlate with different Post-GKRS functional status (p<0.0001) and tumor control (p=0.028). Conclusion: The GSS, used for risk stratification and outcome prediction in patients with meningiomas seems valid for patients undergoing single session GRKS. GSS score greater than 16 is associated with a better long-term functional status and tumor control.