Former England internationals will take part in a study examining the potential effects of concussion on the brain.
Approximately 200 ex-players aged over 50 will be tested, comparing their neurological health with a separate study of the general population.
The Rugby Football Union said "evidence is accumulating" on possible increased risks of neurodegenerative diseases in former contact sport athletes.
England captain Dylan Hartley has said further concussion may end his career.
Hartley was knocked unconscious during the Six Nations match against France on 19 March and only returned to action with his club Northampton on 7 May.
The RFU said the purpose of the study is to see what links can be established between rugby union-related head trauma and conditions such as dementia, amyotrophic lateral sclerosis, Parkinson's disease and chronic traumatic encephalopathy.
Simon Kemp, the RFU's chief medical officer, said: "The RFU has worked extremely hard to increase the education of those involved in the game about concussion and to improve the management of the risk of the injury based on the evidence available.
"The next step for us a union and as a sport is progress beyond delivering 'recognise, remove, recover and return' and try to understand more about the possible longer-term effects on the health of the brain."
The study will be conducted by academics from the London School of Hygiene and Tropical Medicine, Queen Mary University of London, the Institute of Occupational Medicine, University College London and Oxford University.
Professor Neil Pearce, from the London School of Hygiene and Tropical Medicine, will lead the study.
He said: "Each sport is different and there is currently little evidence from rugby players. This study will start to fill this gap, and will allow us to assess whether there are long-term health problems and what their causes may be."