Cornwall's Churches Homelessness Network housing appeal
Cornish householders are being asked to help young people move off the streets by renting them a spare room.
The Churches Homelessness Network said the housing situation in the county was at "crisis point".
It said young people who had been helped by homeless charities needed "move-on" accommodation where they could learn to be independent.
It said a lack of such accommodation meant some young people risked going back on the streets.
The network said Cornish housing charities were finding it increasingly hard to find "move-on" accommodation for people they had helped.
It said houses to rent in the county were "like gold dust" and people forced to live on the streets were desperate to stay in a proper room.
Darren, 22, who used to be homeless, said: "When you're on the streets you're stuck in a catch-22 where you can't get on the first stepping stone until someone steps in to help you.
"As soon as people start helping you, then you feel a lot better about yourself. You don't want to be in a situation where you have no options."
Suzette Crossman, from West Cornwall Young People's Services, runs accommodation and support projects for 16 to 25-year-olds who have been homeless.
She told BBC Radio Cornwall: "They have all sorts of issues but because we work... to empower these young people and get them back into the community they can be such a credit.
"When they're ready to move on they make fantastic tenants."
She said people interested in renting out a spare room should contact Cornwall Council.
The council is currently conducting a survey to establish how many people in the county consider themselves to be homeless.
According to government statistics for autumn 2010, the South West has the highest number of rough sleepers outside of London and the South East.