John Prescott is to declare in the Register of Members' Interests his stay at the ranch of a US billionaire who wants to run the UK's only supercasino.
John Prescott visited the ranch last year
The U-turn came as standards watchdog Sir Philip Mawer began an inquiry into a Conservative complaint about his failure to declare the stay.
The deputy prime minister had said he was on official business, so had not needed to declare it in the register.
He said he wanted to make clear he "acted at all times with integrity".
The row erupted after it emerged Mr Prescott and some of his civil servants stayed at Philip Anschutz's ranch in July last year as part of a nine-day trip to America.
A decision on the location of the first super-casino, allowed under the Gambling Act passed last year, is expected at the end of the year.
The Dome, which Mr Anschutz owns, is among the sites short-listed for the casino.
Under the Ministerial Code, "no minister should accept gifts, hospitality or services from anyone which would, or might appear to, place him or her under an obligation".
Sir Philip's spokeswoman said the standards commissioner believes there is "probably enough substance" in the Tory query "to warrant further investigation".
And Don Foster, the Lib Dems' culture spokesman, said Mr Prescott was "well past his sell by date" and should be "considering his position".
On Tuesday, Mr Prescott told shadow culture secretary Hugo Swire in a letter that he had no reason to register his stay "as my visit to the US was entirely on official business and the cost was entirely covered by public funds".
But Mr Prescott's spokesman said on Wednesday the deputy prime minister had reconsidered that decision "in view of the questions raised and the allegations made".
"The deputy prime minister does not wish there to be any doubt that he has acted at all times with integrity and has, therefore, decided to register the stay by him and his civil servants with the Register of Members' Interests," the spokesman said.
Mr Prescott told Mr Swire his seven meetings with Mr Anschutz took place over a three year period, culminating in the visit to his Colorado ranch last July.
He rejected suggestions that they had discussed the sale of the Dome - which Mr Anschutz's company, the Anschutz Entertainment Group, bought in 2002 - or the award of casino licences.
He also denied then that his stay with Mr Anschutz represented a conflict of interest.
5.24 It is a well established and recognised rule that no minister or public servant should accept gifts, hospitality or services from anyone which would, or might appear to, place him or her under an obligation
"I totally reject the allegations that have been made in the press, and that you repeat, that draw into question the transparency and independence of the decisions made in respect of the Dome or an application for a regional casino," he said.
"I played no role with any planning decision relating to the Dome, or in any negotiations with Philip Anschutz for the sale of the Dome, which were carried out by Lord Falconer at the Department for Transport, Local Government and the Regions and which were completed in May 2002."
Mr Prescott said his first meeting with Mr Anschutz took place in August 2002. His officials were present during all subsequent meetings.
Discussions covered the post-sale use of the Dome, and its possible involvement in London's 2012 Olympics bid, as well as a shared interest in ex-Hull MP and slavery abolitionist William Wilberforce, on whom Mr Anschutz is making a film.
He said Mr Anschutz declined an offer to meet the $600 cost of the stay, so his department made a donation of the same amount to the Red Cross appeal for the victims of the 7 July London bombings.
But Mr Swire says he wants a full statement made to Parliament on Mr Prescott's precise role with respect to casinos.
"Why on earth did the deputy prime minister, the second most powerful political figure in the land, have seven meetings with somebody who wants to bid for the only slot available for a regional casino?" he asked BBC Radio 4's Today programme.
"This is all a smokescreen. What it's trying to do is get away from the central allegations and the questions we are putting."
Downing Street says Tony Blair has "full confidence" in Mr Prescott, adding: "The prime minister believes it is important for ministers to meet large investors in this country."
Sports Minister Richard Caborn said it was "fundamentally wrong" to suggest Mr Prescott would influence the location of the proposed casinos.
But Mr Swire asked if Mr Prescott's role as chairman of the Domestic Affairs Cabinet Committee, which has links to the process that makes recommendations about casino locations, called that claim into question.
Labour's Ian Gibson said he was "astonished" that Mr Prescott had become involved with Mr Anschutz.
"But if you tie yourself up with the rich and powerful, you get your fingers burnt," he told BBC2's The Daily Politics.