The Democratic presidential candidates continued to raise significantly more money during the last three months than their Republican counterparts, according to official and unofficial third-quarter fund-raising tallies that were released yesterday.

Senator Barack Obama, the Illinois Democrat, raised at least $20 million over the summer, more than $19 million of which could be spent on the primary — showing that he continued to be a formidable fund-raiser. It was unclear whether he still led in fund-raising, as he did this spring, because Senator Hillary Rodham Clinton did not release her tally. (Her aides had said that they expected to raise a similar amount.) John Edwards raised $7 million, and Gov. Bill Richardson of New Mexico raised $5.2 million.

By comparison, Mitt Romney, who has been one of the strongest Republican fund-raisers this election, raised only about half of what Mr. Obama raised this summer, according to a senior adviser who was granted anonymity to discuss the campaign’s finances. The adviser said that Mr. Romney brought in about $10 million from donors, and that he used more than $6 million of his own money for his campaign.

Rudolph W. Giuliani, who replaced his chief fund-raiser at the end of the quarter, did not release a tally, but said over the weekend that he thought he would “do as well as the other Republicans — maybe we will do better than some.” Fred D. Thompson raised at least $8 million in his first quarter as a candidate, according to people involved with the campaign — less than the other leading candidates raised early in their campaigns.