"I think the state would be best served if Governor Blagojevich would resign," Madigan told a news conference.
She said she filed a motion with the Illinois Supreme Court, asking the justices to declare Blagojevich unfit to serve in office. She is seeking a temporary restraining order barring Blagojevich from disbursing state funds or making appointments. She said she is hoping the court will act within 10 days.
"We are focused on making sure state government runs for the benefit of the people," Madigan said.
Blagojevich is accused of attempting to sell to the highest bidder the vacated U.S. Senate seat of President-elect Barack Obama for personal gain among other things.
Among those involved in handling the case is former federal appellate Judge Abner Mikva.
"The law gives the authority to the Illinois Supreme Court to make a determination whether the governor is fit to serve ... We're hoping the court will appoint Lt. Gov. (Pat) Quinn to serve" in Blagojevich's place at least temporarily, she said.
The action leaves open the possibility the Illinois Legislature can still move forward with impeachment proceedings. The state House is scheduled to convene next week in emergency session.
Mikva noted the action is temporary and the court action would become moot should Blagojevich resign or be impeached. He said the attorney general's office is hoping the temporary nature of the action will encourage the court to act.
Madigan said she consulted with all the legislative leaders, including her father, House Speaker Mike Madigan, D-Chicago, encouraging them to proceed with impeachment proceedings.