Democratic Sen. Barack Obama's presidential campaign has returned more than $50,000 in political contributions after discovering the donors were lobbyists.

Obama, who has pledged to change the ways of Washington, has repeatedly said he will not accept money from lobbyists or from special interests political action committees.

But as the campaign prepared to file its first quarter finance report to the Federal Election Commission, it also will return $50,566 from 49 donors whom the campaign identified as lobbyists.

Overall, Obama raised $23.5 million for the primary and $25 million overall in the first three months of the year.

"Giving back these donations is part of our best efforts to ensure we stay true to our commitment to not take money from federal lobbyists," campaign spokesman Bill Burton said.

The announcement was designed to get ahead of the FEC report, which must be filed by midnight Sunday. Many of the lobbyists' names will remain listed in the report because their checks were deposited before they were identified.

While shunning lobbyists money, the Obama campaign still has relied on political and policy advice from Washington lobbyists and does accept donations from lobbyists spouses.

"As we've said and as this illustrates, this policy isn't a perfect solution to the problem of money in politics and special interest sway in Washington," Burton said of the decision to return the funds. "But it is an important symbol of the kind of administration that Obama will have in the White House."

Aides said the contributions were inadvertent, possibly the result of lobbyists being unaware of Obama's policy. They said the campaign recognized the donor as a lobbyist after having deposited their check or as the donation arrived.

Among those in Obama's circle of advisers is Broderick Johnson, president of Bryan Cave Strategies LLC, and several other well-connected lobbyists in Washington.

Burton said no lobbyist has performed any fundraising duties for Obama.

John Edwards, the former senator from North Carolina, is another Democratic presidential candidate who has made a point of not accepting money from lobbyists or PACs.