The poll gave Bean a 19-percentage-point lead over Republican opponent Dave McSweeney, with 47 percent of the 400 likely voters backing Bean, compared with McSweeney's 28 percent. The poll, which had a 5 percent margin of error, was conducted for the Democratic Congressional Campaign Committee.

"The poll confirms what we've been saying all along–that suburban families prefer Congresswoman Bean's independent, moderate record over the ideologically extreme views of her opposition," said Bean spokesman Brian Herman in a statement.

McSweeney called the results "preposterous" and suggested the survey was a push poll, with statements misrepresenting his views and questions designed to elicit pro-Bean answers. McSweeney said his own internal polling showed dramatically different results, though he declined to release the numbers.

The new poll's results, first reported by Roll Call and confirmed by the DCCC, also suggest that the Illinois Eighth, which had been in Republican control for decades before Bean's win in 2004 and favored President Bush by 56 percent in 2004, is difficult territory for the GOP this election cycle. Only 40 percent of respondents gave the president a favorable rating, compared with 53 percent unfavorable.

–Will Sullivan