Care home residents are suffering from a lack of information about pricing, access and complaints procedures, a 10-month study has found.
More than 400,000 older people are cared for in homes
The Office of Fair Trading (OFT) said choosing a nursing or residential home was a "major life decision", but the elderly were not given enough support.
It called for a one-stop-shop providing information on the £8bn UK market.
More than 400,000 older people receive care in the UK's 15,700 private, voluntary and local authority homes.
OFT chairman Sir John Vickers said: "Choosing a care home is a life-changing decision often made under distressing and difficult circumstances.
"That makes it all the more important that good information - from both public authorities and care homes - is readily available to help older people and their families, and that fair contract and good complaints procedures are in place for residents."
The study, which was launched after a complaint by consumer group Which?, said clearer information and support was essential as once placed in a home, elderly people rarely moved - even if they were dissatisfied.
About half of care home residents moved into a home after time in hospital, which meant decisions had to be made quickly, the OFT said.
The report said there was a lack of consistency among local authorities over the information they supplied, especially for those not entitled to state funding.
As well as setting up a national gateway providing information on care home, access, pricing and what to do to complain, the OFT said councils should publish directories of care homes in the area and the services they provide.
The OFT also said contracts that self-funded residents sign when entering a home often had unfair or unclear fees.
Jonathan Ellis, policy manager at Help the Aged, said the problems were compounded by the loss of 74,000 care home beds since 1996.
"Many older people face problems getting the care they want," he said.
"The real test will be how, and when, the government responds to these challenges.
Older people should be seen more as "consumers" of long-term care, he added.
Phil Evans, principal policy adviser at Which?, called on the government to act on the "workable" recommendations.
"It [the report] takes a cold hard look at the sector."
And Annie Stevenson, chair of Social Policy Ageing Information Network, an alliance of charities, added it was a "major step forward".
But Sheila Scott, chief executive of the National Care Homes Association, which represents 2,500 independent care homes, said she was surprised by the report as the sector was already heavily regulated.
She said setting up a one-stop-shop was a good idea as there was an over-reliance on the internet for providing information.
A Department of Health spokeswoman said: "We look forward to studying the details of the report and will respond in due course."