A jury has found former Illinois Governor Rod Blagojevich guilty on one count of making false statements to federal officials, with the jury unable to reach a unanimous verdict on 23 other counts.
Blagojevich faced 24 counts in the wide-ranging corruption case including racketeering, conspiracy, mail fraud and attempted extortion.
US District Judge James Zagel said he intends to declare a mistrial on the undecided counts, which will lead to a new trial.
The allegations included an attempt to sell the US Senate seat vacated by President Barack Obama.
Blagojevich faces a potential prison term of five years and a fine of up to $250,000 on the single guilty count.
The verdict on Blagojevich, 53, was delivered after 14 days of deliberations.
Prosecutors said he and his aides operated the state as a money machine by wringing campaign donations out of people doing business with the state.
Though he did not testify, Blagojevich was portrayed by his defence lawyers as a talkative bumbler who received bad advice but never received any illegal funds.
Mr Obama and some senior White House staffers played a peripheral role in the case which was built on FBI wiretaps.
In one tape heard by the jury, Blagojevich cursed that Obama had not offered him a Cabinet post or anything else in exchange for the Senate seat appointment.
