During an appearance on NBC's "Meet the Press," Obama was asked by moderator Tim Russert why he associated someone who was indicted in March on fraud and influence-peddling charges.
Obama called Rezko a friend, but said the indictment was "for issues completely unrelated to me." He acknowledged Rezko had raised about $168,000 for his campaigns, and had helped him buy property even after news of the federal investigation had surfaced.
"I have already acknowledged this was a mistake," Obama said. "Not only should I have not had been involved in any business transaction with him, in particular, but with contributors generally."
Obama said "there was no evidence of wrongdoing" and called the property acquisition "an above-the-board market-based transaction."
"I have not talked to (Rezko) since he got into trouble with the law," said Obama.