OBJECTIVE To evaluate the effectiveness and complications of gamma knife surgery for treating pituitary adenomas. METHODS Retrospective analyses of 217 cases of pituitary adenomas (from July 2004 to November 2008) were performed in Sichuan university's West China Hospital. The patients were treated with an average dose of 26.3 Gy (range 11-33 Gy) and 45%-75% isodose line. Data from serial saddle area MRI and blood endocrine hormone tests were examined. RESULTS Of the 191 patients being followed up, 95.2% had their tumors effectively controlled. All non-functional pituitary adenoma were controlled, with the size of tumor shrinking significantly in an average of 11.4 months after gamma knife surgery. About functional pituitary adenoma were controlled, with the size of tumor shrinking significantly in an average of 18.6 months. Pituitary hypofunction occurred in 11.5% of patients after the surgery. No patient experienced exacerbation of poor eyesight and visual field after gamma knife surgery. CONCLUSIONS Gamma knife can effectively control tumor growth and is a safe and effective treatment for pituitary adenoma.