Background: Medulloblastoma (MB) accounts for less than 1% of adult intracranial tumours. While pediatric MB has been investigated in several randomized studies, the evidence in adults is limited to case reports and retrospective series, with no accepted standard of care. The Australian Cooperative Trials Group for Neuro-Oncology (COGNO) sought to determine the range and consistency of clinicians’ approaches to management as a basis for future trials. Methods: We aimed to identify current treatment strategies for adult MB through an international electronic survey launched at the 2012 meeting of the Society of Neuro-Oncology and by email invitation. Clinicians who had treated at least 1 adult patient with MB, central primitive neuroectodermal tumor (cPNET), or pinealoblastoma in the preceding year were asked about their most recent patient and asked to discuss their approach to management of a typical clinical scenario. Results: Between Nov 2012 and Jan 2013, 45 clinicians (11 medical oncologists, 7 radiation oncologists, 5 pediatric oncologists, and 22 others) from Australia (n = 24), USA (n = 3), Europe (n = 4) and other countries (n = 14) completed the survey. Responding clinicians had treated 54 cases in the past 12 months. The commonest histological type was MB (64%), followed by cPNET (20%). Most patients were male (68%), and most had high-risk disease (65%). 56% had complete surgical resection and 32% had molecular testing. Radiotherapy was predominantly craniospinal (92%) and mostly post-resection (80%). Combination chemotherapy was more common than single agent. Vincristine, cisplatin, cyclophosphamide was the most common protocol (43%). Others included carboplatin, etoposide, ifosfamide (29%), vincristine, lomustine, cisplatin (19%), vincristine, lomustine, prednisone (5%). Further details will be presented at the 2013 ASCO Annual Meeting. Conclusions: Our study has shown substantial international variation in the treatment of adult MB, most pronounced in the choice of chemotherapeutic agents, highlighting the need for further collaborative research to guide evidence-based treatment strategies.