OBJECTIVE: The aim of this study was to evaluate the long-term clinical outcomes of Gamma Knife radiosurgery (GKRS) for residual and recurrent nonfunctioning pituitary adenomas (NFPAs) after surgery and the role of GKRS in the management of NFPAs. METHODS: Between January 2000 and December 2010, 204 patients with residual or recurrent NFPAs undergoing GKRS were enrolled in this study according to the inclusion criteria. The median age of the patients was 48 years (mean, 48 years; range, 14-79 years). The median tumor volume was 3.3 mL (mean, 5.2 mL; range, 0.3-26.4 mL). The median margin dose was 14 Gy (mean, 14 Gy; range, 9-18 Gy). The median maximum dose was 31 Gy (mean, 30 Gy; 20-40 Gy). The median duration of follow-up was 86 months (mean, 88 months; range, 12-213 months). RESULTS: Of these 204 patients, the latest follow-up magnetic resonance imaging studies showed tumor regression in 102 patients (50%), tumor stability in 81 patients (40%), and tumor enlargement in 21 patients (10%). The tumor control rate of this cohort was 90%. The cumulative progression-free survival at 3, 5, 8, 10, and 15 years was 97%, 95%, 92%, 92%, and 81%, respectively. Thirty-seven patients (18%) developed new-onset hypopituitarism, with 1 patient experiencing panhypopituitarism. Five patients (2.5%) presented with new or worsening visual dysfunction without tumor growth. No new cranial nerve dysfunction was shown and no second brain tumor was identified. CONCLUSIONS: GKRS provided high tumor control and a low complication rate in our long-term follow-up. We recommend that early GKRS should be considered the routine adjuvant treatment for residual NFPAs approximately 6 months after subtotal surgical resection.