The authors conducted a retrospective study of patients with large Koos grade 4 vestibular schwannomas undergoing gamma knife radiosurgery. A total of 68 patients with tumour size greater than 4 cm3 with baseline serviceable 60% hearing who received 12 Gray at the 50% isodose line were followed up for an average of 47 months. There was a tumour control rate of 95% at two year and 92% at 10 year follow-up. Most complications post radiosurgery were mild and transient although there were persistent symptoms. The study concludes that even large tumours can be safely and effectively treated with gamma knife and patients with large tumors without significant brainstem compression could be considered for radiosurgery treatment instead of surgery. This study adds to the existing literature on the efficacy of gamma knife in the management of vestibular schwannomas.