Kyiv Appeals Court Judge Iryna Grygoryeva announced the decision after one of the defendants -- former Interior Ministry officer Mykola Protasov -- reportedly felt faint in the courtroom. Protasov and his two co-defendants -- Valeriy Kostenko and Oleksandr Popovych -- face murder charges.
Relatives of the slain journalist and their lawyers said they were "surprised" by the court's decision to adjourn the trial for so long.
Gongadze's mother Lesya has refused to attend the hearings, saying she no longer has faith in Ukrainian justice. At an earlier court session in December, the judicial panel turned down her request to have an additional probe help find those who orchestrated her son's killing.
Gongadze's widow Myroslava, who now lives in the United States, is attending the proceedings. Addressing reporters outside the courtroom, she said those truly responsible for her husband's killing are still on the loose.
"The next step will be when the organizers of this crime will be brought to justice," she said. "They are known, and they must be punished as well as the people sitting in the dock today."
A prime suspect in the case, former Interior Ministry General Oleksiy Pukach, is still at large. Many in Ukraine suspect then President Leonid Kuchma of ordering the assassination. Kuchma denies the accusations.
Audio recordings secretly made in Kuchma's office by a former bodyguard, Mykola Melnychenko, contain a passage in which a voice that is reportedly Kuchma's suggests that Gongadze be "removed and thrown to the Chechens."
Heorhiy Gongadze was neither the first nor the last journalist to be killed in Ukraine, but it is his death that has become synonymous with the pressure exerted on journalists by the administration of former President Leonid Kuchma. Within weeks of his death, secretly recorded tapes emerged that implicated Kuchma in Gongadze's death. Kuchma has always denied any involvement, but the twists and turns of the protracted investigation -- and its failure to produce results -- merely fueled the speculation. The demonstrations triggered by Gongadze's death galvanized opposition to the Kuchma administration.
President Viktor Yushchenko, prime minister at the time of Gongadze's death and leader of the Orange Revolution, has said that resolving the Gongadze case is a "matter of honor." The journalist's alleged killers are now on trial in Kyiv. But a trail of deaths, including one since the Orange Revolution, raise doubts about whether it will ever be certain who ordered Gongadze's murder.
For a timeline of the Gongadze case, click