During the trial in the case called "Prlic and Others" the UN war crimes tribunal (ICTY) heard some 400 witnesses.
The presentation of closing arguments is likely to last two to three weeks.
The trial started on 26 April 2006 on charges of crimes against humanity committed against Bosniaks and other non-Croats in areas which the prosecution alleges the accused wanted to annex to Croatia.
The indictees are Jadranko Prlic, Bruno Stojic, General Slobodan Praljak, General Milivoj Petkovic, Valentin Coric and Berislav Pusic, who have been in the ICTY's detention centre since 5 April 2004.
The six former leaders of the Croat people in Bosnia and Herzegovina are charged according to personal and command responsibility for crimes against humanity, grave violations of the Geneva Conventions and breaches of laws and customs of war committed through the expulsion of several dozen thousand Bosniaks and other non-Croats, killings, rape, deportation, detention of civilians, inhumane and cruel treatment, property destruction, destruction of religious and educational buildings, plunder, and terrorising of civilians.