TOLEDO, Ohio — Senator McCain emphatically denied a romantic relationship with a female telecommunications lobbyist today and said a report by The New York Times suggesting favoritism for her clients is “not true.”

“I’m very disappointed in the article. It’s not true,” the likely Republican presidential nominee said as his wife, Cindy, stood beside him during a news conference called to address the matter.

“I’ve served this nation honorably for more than half a century,” Mr. McCain, a four-term Arizona senator and former Navy pilot, said. “At no time have I ever done anything that would betray the public trust.”

“I intend to move on,” he added.

Mr. McCain described the woman in question, lobbyist Vicki Iseman, as a friend.

The newspaper quoted anonymous aides as saying they had urged Mr. McCain and Ms. Iseman to stay away from each other prior to his failed presidential campaign in 2000. In its own follow-up story, The Washington Post quoted a longtime aide, John Weaver, who split with Mr. McCain last year, as saying he met with lobbyist Ms. Iseman and urged her to steer clear of Mr. McCain.

Mr. Weaver told the Times he arranged the meeting before the 2000 campaign after “a discussion among the campaign leadership” about Ms. Iseman.

But Mr. McCain said he was unaware of any such conversation, and denied that his aides ever tried to talk to him about his interactions with Ms. Iseman.

“I never discussed it with John Weaver. As far as I know, there was no necessity for it,” Mr. McCain said. “I don’t know anything about it,” he added. “John Weaver is a friend of mine. He remains a friend of mine. But I certainly didn’t know anything of that nature.”

His wife also said she was disappointed with the newspaper.

“More importantly, my children and I not only trust my husband, but know that he would never do anything to not only disappoint our family, but disappoint the people of America. He’s a man of great character,” Cindy McCain said.

The couple smiled throughout the questioning at a Toledo hotel.

By this afternoon, the McCain campaign had launched a fundraising appeal based on the Times’s story.

“The New York Times … has shown once again that it cannot exercise good journalistic judgment when it comes to dealing with a conservative Republican,” a McCain campaign manager, Rick Davis, wrote in an e-mail to supporters. “We need your help to counteract the liberal establishment and fight back against The New York Times by making an immediate contribution today.”

“We think the story speaks for itself,” the Times executive editor, Bill Keller, said in a written statement today. “On the timing, our policy is we publish stories when they are ready.”

Mr. McCain’s remaining rival for the Republican nomination, a former Arkansas governor, Michael Huckabee, called Mr. McCain “a good, decent, honorable man” and said he accepted Mr. McCain’s response.

“I’ve campaigned now on the same stage or platform with John McCain for 14 months. I only know him to be a man of integrity,” Mr. Huckabee said in Houston. “Today he denied any of that was true. I take him at his word. For me to get into it is completely immaterial.”

Campaigning in Texas, a Democratic front-runner, Senator Obama, declined to comment on Mr. McCain’s relationship with lobbyists.

The published reports said Mr. McCain and Ms. Iseman each denied having a romantic relationship. Neither story asserted that there was a romantic relationship and offered no direct evidence that there was. Both stories reported that aides worried about the appearance of Mr. McCain having close ties to a lobbyist with business before the Senate Commerce Committee on which Mr. McCain served. The Times said top McCain aides also became “convinced the relationship had become romantic.”

The stories also allege that Mr. McCain wrote letters and pushed legislation involving television station ownership that would have benefited Ms. Iseman’s clients.

In late 1999, Mr. McCain twice wrote letters to the Federal Communications Commission on behalf of Florida-based Paxson Communications — which had paid Ms. Iseman as its lobbyist — urging quick consideration of a proposal to buy a television station license in Pittsburgh. At the time, Paxson’s chief executive, Lowell Paxson, also was a major contributor to Mr. McCain’s 2000 presidential campaign.

Mr. McCain did not urge the FCC commissioners to approve the proposal, but he asked for speedy consideration of the deal, which was pending from two years earlier. In an unusual response, the FCC chairman at the time, William Kennard, complained that Mr. McCain’s request “comes at a sensitive time in the deliberative process” and “could have procedural and substantive impacts on the commission’s deliberations and, thus, on the due process rights of the parties.”

Mr. McCain wrote the letters after he received more than $20,000 in contributions from Paxson executives and lobbyists. Mr. Paxson also lent Mr. McCain his company’s jet at least four times during 1999 for campaign travel.

“Riding on the airplane was an accepted practice,” Mr. McCain said today, adding that he supported a change in rules since then. As for the letters, he said: “I said I’m not telling you how to make a decision; I’m just telling you that you should move forward and make a decision on this issue. I believe that was appropriate.”

Since The New York Times story was published last night, the McCain campaign has sought to discredit it, distributing lengthy statements and deploying senior advisers to appear on news shows. The campaign calls the story a smear campaign to destroy the Republican nominee-in-waiting.

Mr. Keller, the Times editor, explained that the paper’s judgment that the story was ready to print “means the facts have been nailed down to our satisfaction, the subjects have all been given a full and fair chance to respond, and the reporting has been written up with all the proper context and caveats. This story was no exception. It was a long time in the works. It reached my desk late Tuesday afternoon. After a final edit and a routine check by our lawyers, we published it.”

A Washington attorney representing Mr. McCain, Robert Bennett, told NBC’s “Today” show that Mr. McCain’s staff provided the Times with “approximately 12 instances where Senator McCain took positions adverse to this lobbyist’s clients and her public relations firm’s clients,” but none of the examples were included in the paper’s story.

“There is no evidence that John McCain ever breached the public trust and that is the issue and the only issue,” Mr. Bennett, who once represented President Clinton, said today.

Mr. McCain said he won’t allow the reports to distract him from his presidential campaign.

“I will focus my attention in this campaign on the big issues and on the challenges that face this country,” he said.

He defended his integrity last December, after he was questioned about reports that the Times was investigating allegations of legislative favoritism by the Arizona Republican and that his aides had been trying to dissuade the newspaper from publishing a story.

“I’ve never done any favors for anybody — lobbyist or special-interest group. That’s a clear, 24-year record,” he told reporters.

Mr. McCain and four other senators were accused two decades ago of trying to influence banking regulators on behalf of a savings and loan financier later convicted of securities fraud, Charles Keating. The Senate Ethics Committee ultimately decided that Mr. McCain had used “poor judgment” but that his actions “were not improper” and warranted no penalty.

Mr. McCain has said that episode helped spur his drive to change campaign finance laws in an attempt to reduce the influence of money in politics.