The World Association of Newspapers Golden Pen award for journalists facing up to state persecution was awarded to a Chinese journalist for the second year running.
Li Changqing picked up the prize after being imprisoned for three years after reporting an outbreak of deadly dengue fever in 2004, before the Chinese authorities had informed the public of the threat.
His report appeared on a Chinese website based in the US and he was found guilty of distributing "false information".
In a personal message, read out for him by Chinese journalist Li Janghong said: "I am deeply aware that this is not only an award to me in particular but also an award to all my colleagues who are bravely devoting themselves to freedom of speech, especially those in China.
"China is a land that needs to be travelled with the voices of conscience and a nation that needs to be saved by the truth."
Although he was released in February, Li was refused a passport, so could not travel to Sweden.
George Brock, president of the World Editors Forum and editor of the Saturday edition of The Times, paid tribute to Changqing's bravery and criticised China for its intolerance of free speech.
He said: "In most countries he would be celebrated and honoured for his work - in China disclosing such information is an imprisonable offence."
Last year the Golden Pen prize went to Chinese journalist Chitao, who received a 12-year prison sentence for his reporting.
Brock said that in China there are currently 30 journalists and 50 "cyber dissidents" in jail for free speech offences – more than any other country in the world.