BACKGROUND: In the UK, despite the import and use of all forms of asbestos being banned more than 15 years ago, the incidence of mesothelioma continues to rise. Mesothelioma is almost invariably fatal, and more research is required, not only to find more effective treatments, but also to achieve an earlier diagnosis and improve palliative care. Following a debate in the House of Lords in July 2013, a package of measures was agreed, which included a James Lind Alliance Priority Setting Partnership, funded by the National Institute for Health Research. The partnership brought together patients, carers, health professionals and support organisations to agree the top 10 research priorities relating to the diagnosis, treatment and care of patients with mesothelioma. METHODS: Following the established James Lind Alliance priority setting process, mesothelioma patients, current and bereaved carers, and health professionals were surveyed to elicit their concerns regarding diagnosis, treatment and care. Research questions were generated from the survey responses, and following checks that the questions were currently unanswered, an interim prioritisation survey was conducted to identify a shortlist of questions to take to a final consensus meeting. FINDINGS: Four hundred and fifty-three initial surveys were returned, which were refined into 52 unique unanswered research questions. The interim prioritisation survey was completed by 202 responders, and the top 30 questions were taken to a final meeting where mesothelioma patients, carers, and health professionals prioritised all the questions, and reached a consensus on the top 10. INTERPRETATION: The top 10 questions cover a wide portfolio of research (including assessing the value of immunotherapy, individualised chemotherapy, second-line treatment and immediate chemotherapy, monitoring patients with pleural thickening, defining the management of ascites in peritoneal mesothelioma, and optimising follow-up strategy). This list is an invaluable resource, which should be used to inform the prioritisation and funding of future mesothelioma research.