Ratko Mladic's defence case opens at the Yugoslav war crimes court on Monday, with the Bosnian Serb ex-army chief accused of masterminding some of Europe's worst atrocities since World War II.
Mladic, 72, faces 11 charges ranging from hostage-taking to genocide for his role in Bosnia's brutal 1992-95 conflict in which 100,000 people died and 2.2 million were left homeless.
An unnamed witness is to take the stand at 0730 GMT before a three-judge ench of the Hague-based International Criminal Tribunal for the former Yugoslavia (ICTY).
Presiding Judge Alphons Orie has given Mladic's lawyers 207 hours to question witnesses - the same amount of time given to the prosecution, who finished their case earlier this year, the ICTY said in a statement.
There was no restriction on the number of witnesses defence lawyers could call, it added.
Arrested in Serbia and transferred to the ICTY in 2011, the former Bosnian Serb commander is in particular wanted for his role in the June 1995 massacre of almost 8,000 Muslim men and boys at Srebrenica in eastern Bosnia.
There, Mladic's forces overran lightly armed Dutch UN troops protecting the supposedly safe enclave, before murdering the men and boys and dumping their bodies into mass graves.
'Butcher of Bosnia'
Dubbed the "Butcher of Bosnia", the former Bosnian Serb army general is also held responsible for conducting a campaign against residents of Bosnia's capital Sarajevo during a 44-month siege.
Some 10,000 people were killed, many by snipers and shelling.
He has also been charged for taking hostage a group of over 200 United Nations peacekeepers during the conflict, keeping them in strategic locations as "human shields" against NATO air strikes.
Mladic, known for his outbursts in court, has denied the charges. He faces life in prison if convicted.
His lawyers have 207 hours to question witnesses, AFP news agency reported, the same amount of time given to the prosecution team. There is no limit as to how many witnesses can be called.
Last month, the ICTY upheld the charges against him and ruled that Mladic had "a case to answer on all counts of the indictment".
Mladic denies the charges against him.
The hearing will be broadcast on the ICTY website, with a 30-minute delay.