The International Criminal Court (ICC) has agreed to pursue the war crimes trial of Jean-Pierre Bemba, Democratic Republic of Congo's ex-vice-president.
An appeals panel at the court in The Hague rejected an appeal from his lawyers to dismiss the case.
Mr Bemba is accused of leading militias in neighbouring Central African Republic (CAR) in 2002 and 2003.
The troops, which intervened in a power struggle in CAR, are accused of murdering and raping civilians.
But Mr Bemba, 47, has argued that he was not in command of the militia after it crossed the border.
Mr Bemba was arrested in Belgium in 2008 and extradited to The Hague. He is the most high profile suspect so far to be brought before the ICC.
Tuesday's ICC ruling removes the final hurdle to the start of the trial, which has been postponed twice. The ICC says he will face two counts of crimes against humanity and three counts of war crimes.
In his appeal, defence lawyers had argued that Mr Bemba had already been investigated in CAR and could not be prosecuted twice for the same crime.
However, in her ruling ICC appeals judge Anita Usacka said a court of appeal in CAR had upheld the charges against Mr Bemba and referred the case to the ICC.
Judge Usacka said the panel confirmed the decision of an ICC hearing in June that the trial was admissible, and dismissed Mr Bemba's appeal.
The panel also dismissed three other grounds of appeal.
Mr Bemba led a militia known as the Movement for the Liberation of Congo during DR Congo's brutal civil war.
After a peace deal ended the war in 2003, he laid down his arms and joined an interim government as vice-president.
Mr Bemba lost a run-off election against Democratic Republic of Congo President Joseph Kabila in 2006.
One of his defence lawyers has suggested that the charges against him may be politically motivated to remove Mr Bemba from future elections.
ICC judges had been waiting for Tuesday's ruling before setting a trial date.