Retired Judge Eliyahu Winograd, who led the government-appointed commission that conducted the inquiry, called the month-long conflict a "great and grave fumble" with no clear victory over Hezbollah, reported Reuters.
Winograd, however, said Olmert was acting in what he thought was "the interest of the state of Israel," quoted the Associated Press -- largely sparing Olmert from the lashing some had expected from the report.
The commission's preliminary report, released in April, sharply criticized Olmert's actions and prompted calls for his resignation, notably from Foreign Minister Tzipi Livni. Israel's Defense Minister Amir Peretz and Chief of Staff Dan Halutz, who also were faulted in the report, quit their posts after the initial assessment was released.
But Olmert has said renewed negotiations with Palestinian President Mahmoud Abbas are too fragile for him to resign at this point.
"I have no intention of letting go, no matter what the political and personal cost," Olmert said in a speech at a conference last week, according to Bloomberg News.
Olmert launched an air and ground assault on Lebanon in the summer of 2006 to crush Hezbollah fighters and free two Israeli soldiers captured by the militant group, but neither objective was met.
The clashes between Israel and Hezbollah, which pounded northern Israel with rocket fire, continued for 34 days until the United Nations brokered a cease-fire. During the war, 158 Israelis died and at least 1,035 Lebanese were killed.
The April report focused on the first days of the month-long conflict, and the final report critiqued its last days, when Olmert ordered a ground assault even as the U.N.-brokered truce was in the works.
More than 30 Israeli soldiers were killed in the last-minute offensive, which Olmert has contended improved Israel's standing before the cease-fire.
But Winograd said Wednesday that the final offensive did not help Israel's position and the army was not prepared for that battle, reported the AP.