Background: The three treatment options currently considered for vestibular schwannoma are expectant treatment, microsurgery and radiosurgey, and to date no class I evidence favors one treatment over the others. Aim of the study: The objective of this study was to compare long-term functional outcome after gamma knife radiosurgery versus surgical treatment. Methods: A group of 275 patients submitted to microsurgery and 427 patients treated with radiosurgery in two different centers were followed-up for 15.2 ± 13.6 months and 45.6 ± 26.8 months, respectively. We assessed tumor volumetry based on serial MR images, facial nerve function, hearing function, tinnitus, trigeminal symptoms and vertigo, and compared them between treatment groups. Results: Based on normalized volumetry over time, surgery was more efficient for tumor control than radiosurgery (p