Burris, the only black U.S. senator, said he was bowing out of the 2010 race because of the burden of raising money to pay for a campaign.
"I was called to choose between spending my time raising funds, or spending my time raising issues for my state. I believe that the business of the people of the state of Illinois should always come first," Burris said.
"And so today, I have returned to the place where my political journey began back in 1978, back to the South Side of Chicago, back to my community and my constituency to announce, my friends, that I will not be a candidate in the 2010 election, and that I will not run for the United States Senate," he told supporters who minutes earlier had chanted, "Run, Roland, Run!"
His decision caps a long political career that included stints as Illinois' comptroller and attorney general.
Blagojevich appointed Burris to the seat once held by President Barack Obama in December, just weeks after the then-governor was arrested on charges of trying to sell the seat.
After his appointment, Burris fought waves of criticism, opposition from fellow Democrats, court battles and even a perjury investigation. He seemed to acknowledge the travails of the last seven months in his announcement.
"Serving in public life is not easy, but it is a noble and rewarding calling," he said.
Senate Democratic leaders initially vowed not to seat him, but eventually relented when he agreed to give sworn testimony about his appointment to an Illinois panel that was considering impeaching Blagojevich.
He told that panel he had talked to only one Blagojevich associate about the Senate post before it was offered, but later acknowledged other conversations. He denied having any discussions of campaign donations, but it turned out federal investigators had recorded him talking to Blagojevich's brother about the possibility of raising money for the governor.
Burris has maintained he did nothing improper to get the seat. A prosecutor who looked into whether Burris should be charged with perjury for his incomplete testimony to the impeachment panel concluded it would be impossible to prove.
