The Chicago Tribune-WGN poll finds 50 percent of the 500 Democrats surveyed prefer Obama, while 25 percent like Sen. Hillary Clinton. The New York senator is a Chicago native who grew up in the suburb of Park Ridge.
Former Sen. John Edwards was a distant third with 7 percent.
Democratic voters were split almost evenly on who is most likely to win in November with 39 percent saying Clinton was most electable and 37 percent Obama.
On the Republican side, former Arkansas Gov. Mike Huckabee is almost even at 21 percent with former New York Mayor Rudy Giuliani at 23 percent. Former Massachusetts Gov. Mitt Romney got 14 percent, Sen. John McCain of Arizona 12 percent and former Sen. Fred Thompson 11 percent
The poll is the first among likely voters in the Illinois primary, scheduled this year for Super Tuesday, Feb. 5.