Democratic voters in Fairfield County will have the opportunity to vote in an August 12 primary.
There are now two Democrats vying to run against Republican Incumbent Chris Shays in the fall.
According to Secretary of the State Susan Bysiewicz, Lee Whitnum of Greenwich has enough signatures to challenge the Democratic party's endorsed candidate, Jim Himes, a former banker and current vice president of a community affordable housing organization.
On her website, Whitnum says she's a substitute teacher and an average American woman.
Whitnum says she's running to represent the voice of mainstream America.
"The people don't want an elitist Greenwich Wall Street candidate. They want a candidate who will fight for their best interests. A candidate who will fight for jobs and the interests of the middle class."
However, state Democratic party Chairwoman Nancy DiNardo says the primary is a distraction to the party's goal to unseat Shays this fall.
"Jim Himes has been at this for over a year. He's done a phenomenal job in raising money and he's been out there with the issues. My contact with Lee has been sporadic throughout this whole process. She would call and say she'd wants to go to a town committee meeting and then nobody would hear from her for a long time. So, I'm just surprised at the last minute she decided to get the signatures and try to make it a Primary."
Dinardo says Himes got an unanimous endorsement at the party's Convention last month while Whitnum did not attend.
This will be the first primary in the 4th Congressional District since 1987, when a special election was held to fill the vacancy created by the death of Rep. Stewart B. McKinney.