The district was redrawn and now includes more Democrats in the western and southwest suburbs.
Foster greeted voters at Brooks Middle School in Bolingbrook Tuesday.
Biggert is the incumbent trying to hang on to her seat in this close race.
"Unfortunately, my district was cut into six pieces. I have part of it, fortunately, but it really is a different district. But it's a great district," said Biggert.
"It's middle class district and, you know, I feel very strongly that this race is about the health of the middle class, and I'll do quite well in this, because I think people understand that we need someone to fight for the middle class," said Foster.
Both candidates have seen the influence of national party money and advertising has been pointed and inflammatory.
"We have to have a serious discussion about the influence of money, putting money behind big lies on television. This is not the way democracy should operate. Today it is the voters, the boots on the ground that will win this," said Foster.
"It is ugly but, you know, I have always thought being positive was all you needed to do. But I think the state of these races this year has been much different than before," said Biggert.