Maxim Bakiyev - the son of ousted Kyrgyz President Kurmanbek Bakiyev - has been sentenced in absentia to 25 years in jail for corruption.
A Kyrgyz court found him guilty of signing agreements that lost the country hundreds of millions of dollars while his father was in power.
Maxim Bakiyev is in the UK, where he was arrested and granted bail last year on separate fraud charges in the US.
He fled Kyrgyzstan in 2010 when his father was overthrown in an uprising.
Known as "The Prince", Maxim Bakiyev, 35, was one of the most powerful men in Kyrgyzstan during his father's five-year rule.
The court in the capital Bishkek found him guilty of illegally privatising public land around a popular tourist resort when he was head of the Central Asian country's national investment agency.
It also said he had sold off state energy firms for a fraction of their value.
Kyrgyz prosecutors said they would continue efforts to have him extradited from London.
Maxim Bakiyev is also facing an extradition request from the US on charges of conspiracy to commit securities fraud and obstruction of justice.
At an earlier hearing his lawyers told a London court they suspected the charges were politically motivated because of Washington's strategic interests in Kyrgyzstan, where the US operates an air base.
His father - former President Kurmanbek Bakiyev - has also been convicted in absentia but has been given asylum in Belarus.
The former leader was sentenced to 24 years in jail in February over the murder of a senior official in 2009 and is also accused of mass murder over the the shooting of dozens of people by police during the revolt that toppled him.
Maxim Bakiyev's brother Zhanysh, who led the security services and is also thought to be in Belarus, was given a life term for crimes including murder.