The Radical Party leader, dressed in a dark suit with a large briefcase at his side, sat in the same courtroom used to try Milosevic, who died in detention in The Hague in March 2006 before his trial ended.
Like Milosevic, Seselj has accused the the International Criminal Tribunal for the former Yugoslavia of bias against Serbs and has repeatedly disrupted proceedings.
"I am being tried for atrocious war crimes that I allegedly committed through hate speech as I preached my nationalist ideology that I am proud of," he said in a pre-trial hearing.
"I have no other involvement in these crimes expect for what I said or wrote."
Seselj is accused of making speeches calling for the creation of a "Greater Serbia" and of recruiting, financing and supplying Serb paramilitary units and volunteer fighters who went on to commit atrocities.
He is charged with murder, torture, persecution, cruel treatment, deportation, inhumane acts, wanton destruction and plunder.
The trial had been set to begin late last year but Seselj began a hunger strike for 28 days after the court refused him permission to defend himself and imposed defence lawyers on him to try and speed up proceedings.
He eventually won back the right to self-defence.
In Belgrade, the Serbian capital, Seselj's party distributed posters of their leader that read "The trial begins - end Hague tyranny".
Aleksandar Vucic, the party secretary, said the Radicals did not expect a fair trial but were sure Seselj would prove Serbia was not guilty of war crimes.