The ICTY has proved that it is possible to try even the most complex cases, including for the worst crimes, against the highest military and political leaders, and do so in many cases, Meron told a conference on the tribunal's 20th anniversary and achievements.
He said the decision to establish the ICTY, made by the UN Security Council in 1993, had been historic.
After half a century of inaction and after the trials of the Nazi war criminals, the international community strongly responded to the atrocities committed during fierce war conflicts, said Meron.
He recalled that many had doubted the ICTY's efficiency and that some verdicts were and remained contradictory.
Some argue that the tribunal's verdicts did not bring justice to the victims, while others wonder about its contribution to history. Still, we must remember that the tribunal's mandate is quite limited and that its task is to find the accused guilty only when guilt is proved beyond reasonable doubt and on the basis of evidence. By adhering to this principle, the ICTY eliminated in these 20 years all the initial doubts and surpassed expectations, Meron said.
He said the ICTY could be proud because it respected the equity of trials, considering everyone innocent until proven guilty. He recalled that the tribunal had collected a remarkable body of evidence which would serve many generations, and that tribunals like the International Court of Justice were a direct legacy of what the ICTY had started.
Meron also recalled the residual mechanism, established to bring to completion possible appeals in the cases of Radovan Karadzic, Ratko Mladic, Vojislav Seselj, and Goran Hadzic.
Until then, we remain focused on responsibly wrapping up the ICTY's work, he said, adding that now there was increasingly more work in trying war crimes before the national judiciaries, notably in Bosnia and Herzegovina.
A group of nongovernmental activists, disgruntled by Meron's presence at the Sarajevo event, walked out of the conference hall before his address carrying a banner which said "RIP Justice".
"We don't want to be part of a circus which allows Judge Theodor Meron to wash his hands of the responsibility to explain the disastrous decisions he handed down," reporters were told by Hana Obradovic, one of the organisers of the protest. She said there were no answers to questions about the contradictory early releases of those convicted of war crimes.
Munira Subasic, president of the "Mothers of Srebrenica" association, was also dissatisfied with the ICTY's track record and Meron's activity. She divided the tribunal's effects in two stages, with the Slobodan Milosevic trial as the watershed.
"We were happy with the Hague tribunal until the moment Milosevic died. When Milosevic died, justice for the victims died too," she told Hina, adding that the ICTY should have found a mechanism to sentence Milosevic for the crimes.
"We fear that a similar scenario might occur in the cases of Mladic and Karadzic too," she said, adding that recently the ICTY "has been doing absolutely nothing" because it was not contributing to justice and reconciliation.
Subasic described as unacceptable the release of convicts after they had served two-thirds of their sentences. "That's all Meron's doing."
Bosnian Presidency member Bakir Izetbegovic told the conference that his opinion on the ICTY's work was mixed.
"I can't shake the impression that there are two (ICTY's)," he said, adding that the first one, established in 1993, sent a clear message that crimes must be punished and that there was indeed justice in this world.
He described as the most significant verdicts those on the genocide in Srebrenica, the siege of Sarajevo, and on systematic rape as a war crime.
"Unfortunately, in the time that followed, the tribunal moved away from that. The tribunal became tired and set wrapping up its work as its only goal," Izetbegovic said, describing as dubious the acquittals on appeal of the highest military and political officials responsible for war crimes.
"How to explain that those sentenced to 20 or more years were acquitted on appeal?" he said, adding that such sentences affected the victims the most.
Izetbegovic voiced hope that in the remaining trials the ICTY would complete its job "in a just way."
Bosnian State Court president Meddzida Kreso said the ICTY had considerably contributed to the establishment of the war crimes department at the State Court, including its witness protection programme and trials for joint criminal enterprises and superior responsibility.
"I hope the State Court and its war crimes department will continue to have such support for its future work," she said.
The director of the International Commission on Missing Persons (ICMP), Kathryne Bomberger, recalled that the requirement of the ICTY trials had been the collection of a large body of evidence which, she said, involved an entire army of forensic experts and anthropologists who exhumed victims' bodies from numerous mass graves.
More than 3,000 mass graves have been dug up on the territory of the former Yugoslavia, she said, adding that this experience would be used in all future conflicts, including in the war in Syria.
Participating in the ICTY's investigations, the ICMP helped to establish what happened to 70 per cent of more than 40,000 reported as missing during the 1990s wars in the former Yugoslavia.
The Sarajevo conference, organised by the ICTY, drew representatives of the tribunal, the Bosnian judiciary and many NGOs from the region which represent crime victims and the families of the missing.