More than 35 million people worldwide had dementia in 2010, when annual costs were estimated at USD 604 billion; the number of people with dementia is expected to exceed 115 million by 2050. Alzheimer’s disease is today considered the prototype problem for the Grand Global Challenge in healthcare. Despite decades of intensive research, the causal chain of mechanisms behind Alzheimer’s has remained elusive as reflected in recent failures of well-designed clinical trials on promising investigational new drugs. The multi-factorial nature of the disease requires the collection, storage and processing of increasingly large and very heterogeneous datasets (behavioural, genetic, environmental, epigenetic, clinical data, brain imaging, etc.). No one nation has all the assets to pursue this type of research independently. In an effort to tackle this huge challenge, the OECD held a consultation on "Unlocking Global Collaboration to Accelerate Innovation for Alzheimer’s Disease and Dementia" which looked at ways to harness developments in life sciences and information technologies to accelerate innovation in the prevention and treatment of the disease. This paper reports on the opportunities offered by the informatics revolution and big data. Creating and using big data to change the future of Alzheimer’s and dementia requires careful planning and multi-stakeholder collaboration. Numerous technical, administrative, regulatory, infrastructure and financial obstacles emerge and will need to be hurdled to make this vision a reality.