Rewarding young people for their work in the community was a "powerful antidote" to this summer's riots, the Prime Minister has said.
David Cameron was meeting "unsung heroes" who have been nominated to receive a Spirit of London Award (SOLA) at Downing Street.
The awards aim to be a "Community Oscars" in which celebrities applaud young people who use their time and skill to build strong communities.
Mr Cameron hailed the nominees as "young people doing great things that we can all be proud of" and described the awards as a "powerful antidote to what we saw in the summer", in reference to the violent outbursts which took place in England last month.
He said: "In the Spirit of London Awards we celebrate the best of the capital's young people.
"When I go round the country I meet young people more hopeful, more energetic, more fired up to change their neighbourhood and change the world than any in my generation. Spirit of London is a fantastic example of that."
The 2011 awards are split into 11 categories, which range from young London hero (ages five to 16) to achievement through the arts, to young business entrepreneur.
Among this year's nominees is table tennis player Darius Knight, who aspires to the achievement through sport gong.
The 20-year-old grew up in Battersea, south London, surrounded by gangs and drugs but has managed to become a sporting star representing Britain on the table tennis World Pro Tour.
Knight said: "Of the gang of 15 that I used to hang out with, only three of us have done something positive with our lives. I was lucky because table tennis offered me a way out. If we could get more sporting opportunities for kids in places like that, it would give others a way out too."