Romania's highest court on Monday sentenced former Prime Minister Adrian Nastase to two years in prison after convicting him of illegally raising funds for a failed presidential campaign.
The ruling is the first time a former Romanian premier has been sentenced to prison since communism ended in the country in 1989.
Four others in the case received six-year prison sentences. The sentences can be appealed.
Nastase, who was prime minister from 2000 to 2004, insists he is innocent and that the case is politically motivated. He said he would appeal.
Prosecutors alleged that companies and state agencies were forced to pay fees to attend a conference in 2004, and the money was then used to pay for Nastase's unsuccessful run for the presidency in 2004. He lost the runoff to President Traian Basescu.
"The one that won the elections wanted to take revenge on the one that lost," Nastase said Monday.
Romania is under pressure from the European Union, which it joined in 2007, to crack down on endemic corruption.
Romania will hold local and parliamentary elections later this year. Observers expect these to be the most bitterly contested polls of recent years.
Thousands of Romanians who have staged anti-government demonstrations for the past two weeks say they are sick of corruption and cronyism as well as falling living standards which they blame on the government's austerity measures.
Nastase, a key member of the opposition Social Democracy Party, was cleared in December of corruption charges in another trial where he was accused of paying a bribe to a government official in charge of preventing money laundering to destroy documents regarding a bank deposit of $400,000 (euro308,000) by Nastase's wife.
Nastase has always claimed the money deposited in his wife's account came from her aunt's sales of paintings and rare books.