Objective: To describe the clinical, radiologic and histopathologic features of endolymphatic sac tumors using the St Vincent's Hospital experience with these tumors to highlight important aspects of tumor diagnosis and treatment. Possible explanations are given for the apparent increasing incidence of these tumors. Study Design: Retrospective review of the senior author's (P.A.F.) database of skull base lesions. Setting: Tertiary referral teaching hospital. Patients: All patients with a proven diagnosis of endolymphatic sac tumor treated at St Vincent's Hospital, Sydney. Outcome Measures: Survival in months, after surgery. Results: Seven cases of endolymphatic sac tumors. All were treated surgically. Mean follow-up of 70.2 months (range, 6-144 mo). Conclusion: Endolymphatic sac tumors are becoming increasingly recognized because of awareness of their existence as a separate entity from middle ear tumors. This has been achieved by improved imaging and histopathologic techniques. Surgery is the mainstay of treatment.