Lord Hutton's long-awaited report into the death of Dr David Kelly will be published on 28 January.
Lord Hutton's hearings went on for six weeks
The report will be published in Parliament and Lord Hutton will make a televised statement about his findings.
Dr Kelly apparently committed suicide last July after being named as the suspected source for the BBC's controversial Iraq weapons story.
Its publication will come the day after a key Commons vote on the controversial plans for university top-up fees.
24 hours notice
Downing Street says the timing of the report was "entirely a matter for Lord Hutton".
A spokesman declined to say whether the prime minister regretted that the report was to be published the day after the crucial vote.
Lord Hutton heard evidence from 74 witnesses over six weeks and saw thousands of pages of documents.
His report is being sent to the printers on 19 January but will also be published on the inquiry website.
The six parties represented at the inquiry - including the government, Dr Kelly's family and the BBC - will get 24 hours notice of its findings.
But they will have to promise not to reveal its contents before publication.
Questions remain on how much advance sight opposition parties will get of the report.
Downing Street says that will be decided "at the appropriate time".
That prompted Conservative leader Michael Howard to demand "earliest possible sight" of the report before its publication.
And he said it had been "completely untrue" when Mr Blair suggested at a news conference that Lord Hutton should decide when opposition parties saw the report.
Liberal Democrat leader Charles Kennedy said there should be no repeat of the way opposition parties were given little time to study the Scott Report into the Arms to Iraq affair.
Tony Blair will make a House of Commons statement on the day it is published.
His spokesman said he would also lead the full Commons debate on the report, likely to be held the week after its publication.
But he would not say whether MPs would get a chance to vote on it.
Dr Kelly's death came after BBC Today programme defence correspondent Andrew Gilligan's report on claims that Downing Street "sexed up" the government's Iraq weapons dossier.
The BBC has come under fire for the way it handled complaints about the broadcast.
Scrutiny over the government surrounds the preparation of the dossier and the way Dr Kelly was treated once he admitted meeting Mr Gilligan.
The Tory leader has continually pressed Mr Blair about his statement to reporters that he did not authorise the naming of Dr Kelly.
Mr Blair has accused the Tories of rushing to judgement and urged people to wait until Lord Hutton's findings are published.
Lib Dem foreign affairs spokesman Sir Menzies Campbell said: "Between them top-up fees and Lord Hutton's report could seal the fate of this government."
But he argued the narrow circumstances around Dr Kelly's death should not divert attention from the central question of why Britain went to war in Iraq on a "false prospectus".
The BBC press office declined to comment on the date announcement.