For the first time the government is to calculate the number of adults with autism in England.
Announcing the £500,000 project, Care Services Minister Ivan Lewis said autistic adults are too often abandoned by health and social services.
The National Autistic Society welcomed the move, saying it hopes it will mark a turning point in the way the needs of adults with autism are met.
The statistics will be used to form a national strategy.
The challenge for the researchers will be to make sure people whose autism has not yet been diagnosed are not overlooked.
In making the announcement, Ivan Lewis highlighted how limited the understanding of the condition still is.
"We still don't know enough about autism, but we do know that left unsupported, it can have a devastating impact on those who have the condition and their families.
"One of the key gaps in our knowledge is simple - we don't know how many people have the condition in any given area.
"That is why I am ordering a study to address this."
The National Autistic Society describes the condition as a complex disability affecting someone's development and a defect in the way the brain functions.
Asperger Syndrome is a form of autism where people sometimes have high intellectual and verbal abilities, but it is still very disabling, and people with it can find many ordinary daily activities such as cooking, shopping, handling money, making phone calls almost impossible.
Autism is often associated only with children, but it is a lifelong disability with no cure.
There has been academic research into the prevalence of autism amongst children in the UK and that suggests it is one in every 100.
Adults with autism told us they feel isolated and ignored
National Autistic Society
Your experiences of autism
But until now, there has been no specific study into how many adults have the condition.
The group has been hard to measure partly because so many people have grown up before improvements in recognition and diagnosis; and some may have been labelled inappropriately as having mental health problems or learning difficulties or not acknowledged at all.
Academics at the University of Leicester will lead the research which will include a study of a sample of the adult population - a sort of mini census .
Their challenge will be to find some way of taking account of those adults who have not been diagnosed to achieve as much accuracy as possible.
Once the work is complete, the government will use the statistics to craft the first national strategy for adults with autism to be published next year.
The National Autistic Society has long campaigned for this research to be done and is enthusiastic about the move.
Chief Executive Mark Lever said: "This is great news for the thousands of adults with autism who told us they feel isolated and ignored.
"We are delighted that the government has listened and is taking decisive action. Today's announcement should mark a sea change in the way that the needs of people with autism are recognised and met.
"However, we will keep campaigning to ensure real change happens at ground level."
Geoffrey Maddrell, chairman of the charity Research Autism added: "This is an important first step towards understanding the scale of autism in the UK and will help to decide what next steps need to be taken to ensure people with the condition are supported and signposted toward approaches that will enhance their quality of life."