Sen., second to none in the race for campaign cash, raised more than $40 million in March and boosted his vast network of donors to nearly 1.3 million, the campaign announced Thursday.
The amount is less than the record $55 million he raised in February, but still a sizable amount that sustains his place as the fundraising leader among all presidential candidates. The money gives him a substantial financial advantage over Democratic rivalas they compete for votes heading into the April 22 Pennsylvania primary.
Clinton raised $20 million in March, the second best showing of her campaign, aides said. Clinton has raised nearly $70 million this year. Details of the candidates' March fundraising will be made public in official reports filed with the Federal Election Commission April 20.
The Obama campaign said it attracted more than 218,000 first-time donors in March.
"Many of our contributors are volunteering for the campaign, making our campaign the largest grass-roots army in recent political history," campaign manager David Plouffe said.
Obama has been the candidate most successful at blending high dollar donors with small contributions by deft use of the Internet. He has had the highest number of donors contributing $200 or less.
"We knew that he was going to outraise us," Clinton communications director Howard Wolfson said. "He has outraised us over the last several months."
Wolfson said the campaign will have the resources they need to compete and be successful in the upcoming primaries. He pointed to Clinton's base of support from online fundraising, saying she had raised about $1 million online on March 31.
Obama's announcement comes as both Democrats return to a popular financial wellhead, raising money in California to help finance a heavy stretch of spending in April. With their race for the Democratic nomination showing no signs of ending, tapping donors for more cash has new urgency.
Obama has scheduled fundraisers at the homes of four different financial backers Sunday afternoon and evening in northern California. Clinton attended one fundraiser Wednesday in Silicon Valley, and had three planned for Thursday - in San Francisco, Pasadena and Los Angeles.
Most of the events are for donors giving the $2,300 maximum allowed by law.
Obama raised a record $55 million in February; Clinton raised $34.5 million.
Though the New York senator trails Obama in delegates needed for the nomination, Clinton advisers and fundraisers said her donors remain enthusiastic. But her fundraisers also say she relied too much on large donors early in the cycle.
The Money Race
Check out February tallies for Clinton, Obama and McCain, including how much they've raised and spent since the campaign began.
"That pool is reduced," said Larry Stone, a Clinton fundraiser in Silicon Valley who also is the Santa Clara County assessor. "Hillary came really late to the game in effective fundraising on the Internet as compared to Barack Obama ... Many of the solid enthusiastic Clinton supporters were maxed out."
But Stone added: "A big boon to the fundraising has been these appeals for her to withdraw. It makes supporters angry, especially women."
Clinton aides said Wednesday that they anticipate Obama will outspend her by 2-to-1 in Pennsylvania. In the first round of campaign ads, Obama spent about $2 million to Clinton's $450,000, according to data compiled by TNS Media Intelligence/Campaign Media Analysis Group, which tracks political ads. Obama is also already airing ads in Indiana and North Carolina, which won't hold primaries until next month.
"We don't expect to match Senator Obama ad for ad," Wolfson told reporters during a conference call Wednesday.
Clinton entered March with $11.5 million to spend in the primary compared to $30.5 million for Obama. Moreover, Clinton owed $8.7 million to several campaign vendors at the end of February. A spot check by The Associated Press of several vendors found many were paid last month, after the March 4 primaries in Ohio and Texas. The cost of those two contests, together with efforts to reduce campaign debt, have kept fundraising a priority for her campaign.