Gov. Rod R. Blagojevich of Illinois was arrested by federal authorities on Tuesday morning and charged with corruption, including an allegation that he conspired to profit from his authority to appoint President-elect Barack Obama’s successor in the United States Senate, prosecutors said.

As Mr. Blagojevich, a Democrat, mulled the Senate appointment, prosecutors say, he discussed gaining “a substantial salary” at a nonprofit foundation or organization connected to labor unions, placing his wife on corporate boards where she might earn as much as $150,000 a year and trying to gain promises of campaign money, or even a cabinet post or ambassadorship, for himself.

A 76-page affidavit from the United States Attorney’s office in the Northern District of Illinois says Mr. Blagojevich (pronounced bluh-GOY-uh-vich) was heard on wiretaps over the last month planning to “sell or trade Illinois’ United States Senate seat vacated by Pres-elect Barack Obama for financial and personal benefits for himself and his wife.”

The charges are part of a five-year investigation into public corruption and allegations of “pay to play” deals in the clubby world of Illinois politics. Federal authorities said Mr. Blagojevich’s chief of staff, John Harris, was also indicted on Tuesday. Both men are expected to appear in federal court for the first time later Tuesday.

Mr. Blagojevich, a Democrat in his second term who came into office in 2002, portrayed himself as a reformer after the one-term of the former governor, George Ryan, who was convicted of racketeering and fraud in 2006.

For more than a year, members of Mr. Blagojevich’s administration have been under investigation. But few here have imagined that the decision on replacing Mr. Obama might have resulted in criminal charges.

In addition to the charges related to Mr. Obama’s Senate seat, Mr. Blagojevich is accused of crimes related to past behavior. As part of the charges, he is accused, prosecutors say, of working to gain benefits for himself, his family and his campaign fund in exchange for appointments to state boards and commissions.

Under Illinois law, Mr. Blagojevich has sole authority to fill the seat being vacated by Mr. Obama, who was elected to the Senate in 2004.

According to the indictment, while talking on the telephone about the Senate seat replacement with his chief of staff and an adviser, Mr. Blagojevich said he needed to consider his family and their financial struggles. “I want to make money,” he said, according to prosecutors. He then added, they allege, that he wanted to make $250,000 to $300,000 a year.

In a release, Patrick Fitzgerald, the prosecutor, said Mr. Blagojevich “put a for sale sign on the naming of a United States Senator.”

Mr. Blagojevich even contemplated stepping into the Senate himself, prosecutors said.

“I’m going to keep this Senate option for me a real possibility, you know, and therefore I can drive a hard bargain,” Mr. Blagojevich said in a recorded conversation with an adviser, according to the affidavit. “You hear what I’m saying. And if I don’t get what I want and I’m not satisfied with it, then I’ll just take the Senate seat myself.”

According to the affidavit from prosecutors, Mr. Blagojevich told an adviser last week that he might “get some (money) upfront, maybe” from one of the candidates hoping to replace Mr. Obama. That person was identified only as “Candidate 5.”

In an earlier recorded conversation, prosecutors say, Mr. Blagojevich said he was approached by an associate of “Candidate 5” with an offer of $500,000 in exchange for the Senate seat.

The authorities also say Mr. Blagojevich threatened to withhold state assistance from the Tribune Company, the publisher of the Chicago Tribune and Los Angeles Times, which filed for bankruptcy on Monday. According to the authorities, Mr. Blagojevich wanted members of the Tribune’s editorial board, who had criticized him, to be fired before he extended any state assistance.

An official at the governor’s office had no immediate comment on Tuesday. A telephone message left at Mr. Obama’s transition office was not immediately returned.

Jack Healy contributed from New York.