Gov. Pat Quinn claimed victory in the Democratic primary over Comptroller Dan Hynes, though the margin was less than 1 percent. Though President Barack Obama called Quinn to offer his congratulations, Hynes has refused to concede.
On the Republican side, State Sen. Bill Brady led by just a few hundred votes over State Sen. Kirk Dillard.
Quinn is trying to win the job on his own merits after inheriting it a year ago when Rod Blagojevich was ousted in disgrace over charges including the allegation that he tried to sell Obama's former Senate seat. He said it was time for Democrats to unite and focus on keeping the governor's seat in November.
"The time for fighting is over," Quinn said as he thanked voters at a Chicago train station. "The tradition in our party is that people come together after the primary and work together for the candidates in the fall."
Hynes campaign manager Michael Rendina said the nomination could hinge on how many absentee and provisional ballots remain to be counted.
Tuesday's first-in-the-nation primary did decide the field in the race for the U.S. Senate seat formerly held by Obama. Democrat Alexi Giannoulias, the state treasurer and a basketball buddy of the president, will face five-term U.S. Rep. Mark Kirk.