Freshman Rep. Eric Massa (D-N.Y.) is expected to announce on a 3:30 p.m. conference call that he will not run for a second term in November.
A source who has spoken to Massa said the Congressman will announce he is leaving because of a recurrence of cancer. Massas retirement was first reported by the New York Daily News on Wednesday afternoon.
Massa was first elected in 2008, when he defeated then-Rep. Randy Kuhl in the Republican-leaning 29th district.
Republicans had been targeting Massa for defeat in November, and the race to succeed him will likely be competitive.
He will become the 15th Democrat to announce plans to leave the House at the end of this year.
United We Dream protesters carry a mock coffin to the office of Sen. Ted Cruz, R-Texas, in the Dirksen Senate Office Building on Monday, July 21, 2014, to hold one of their "funeral services for the Republican Party" due to GOP positions on immigration. The immigration reform group visited several other Senate Republican offices to hold similar funeral services.