Front-running Republicans Rudy Giuliani and Mitt Romney outpaced the rest of the GOP presidential field in summer campaign fundraising, but newcomer Fred Thompson was hot on their heels.

Giuliani raised more than $11 million for the presidential race in the July-September quarter, $10.5 million of it available for the primaries. Romney raised $10 million and tapped his personal fortune to pump in an additional $8.5 million.

Thompson, the former Tennessee senator and "Law & Order" television actor, raised $9.3 million in the quarter and attracted 80,000 donors. He joined the GOP campaign only last month but had been raising money all along.

Giuliani's income left him with $16 million cash on hand, aides said Thursday. Of that, about $12 million is available for the primaries. Romney had $9 million on hand to compete for the Republican nomination. Thompson had $7 million in the bank. All of Romney's and Thompson's money is available for the primaries.

Romney's personal contribution nearly matched the amount he had invested in his campaign for the first six months of the year. Overall, Romney, a former venture capitalist and Massachusetts governor, has dipped into his personal wealth for nearly $17.5 million.

"Writing checks is always painful for me, no matter what it's for, but I nonetheless recognize this is a critical race," Romney told reporters in Manchester, N.H., on Thursday. "There is nothing more important to me than the success of this nation, and I know a lot of people are sacrificing to help my campaign, and I will certainly be contributing in my own campaign."

John McCain, fighting to get back with the Republican front-runners, raised $6 million in the past three months and has $3.6 million cash on hand, his campaign said.

McCain aides said the fundraising and the financial condition of his campaign represent a turnaround for the Arizona senator, whose spending during the first six months of the year strained his budget while his polling numbers plummeted.

McCain was expected to report a debt of about $1.5 million, less than he reported at midyear.

Romney's ability to write his campaign checks has given him the resources to spend heavily on advertising throughout the year, particularly in Iowa where he was hardly known when he began his presidential effort. Without his third-quarter contribution, Romney would have only about half a million dollars in the bank going into a heavy spending stretch of the campaign.

His personal assets are estimated at between $190 million to $250 million, making him the wealthiest of all the candidates in both parties.

The fundraising quarter ended Sunday, and campaigns from both parties have been strategically releasing their top numbers over the week. The candidates must file detailed reports on fundraising and spending by Oct. 15 to the Federal Election Commission.

So far in the presidential contest, Romney has raised about $45 million from contributors. Including his own money, his campaign's total receipts are more than $62 million. Giuliani is not far behind with more than $44 million, but about $4 million of that can be spent only in the general election — if Giuliani wins the nomination. Romney is not raising any general election money.

The two Republicans lag far behind the two Democratic Party money leaders — Hillary Rodham Clinton and Barack Obama. Clinton has raised about $63 million for the primary and about $17 million for the general election. She also has transferred $10 million left over from her 2006 Senate campaign. Obama has raised about $75 million for the primary contest and about $4 million for the general election.

Giuliani is ahead of the Republican field in national polls. Romney leads in polls in the early voting state of Iowa and is in a tight contest with Giuliani and McCain in New Hampshire.

In a surprise to the GOP field, anti-war Republican Ron Paul raised $5 million in the third quarter and has $5.3 million cash on hand, more than McCain. Paul's opposition to the war has mobilized an avid Internet base of support for his long-shot candidacy.

Giuliani's campaign hailed his own top fundraising performance as evidence that he is best positioned to win the general election.

"We're receiving real support from across the country because voters know Rudy Giuliani is the only candidate who has proven leadership, executive experience and can beat the Democrats in November," campaign manager Mike DuHaime said.

Giuliani's cash-on-hand amount is the most significant because it gives him a $3 million advantage over Romney as the campaigns head into an intense segment of the contest, with the earliest voting only three months away.

But Romney's willingness to use his own money adds a measure of uncertainty. His wealth gives him ready access to cash to confront political challenges in those January elections.

McCain, who ended the second quarter with little cash and a staff upheaval on his hands, still has a financial challenge ahead of him. But his campaign said he has steadied his spending, cutting monthly expenditures from $4.5 million to $1.5 million.