Republican Party officials say Dennis Hastert, the former speaker of the U.S. House of Representatives, will not seek re-election in the 2008 general elections.
Hastert served as House speaker from 1998 until January of this year, when the Democrats took control of the chamber, making him the longest-serving Republican speaker.
He is expected to formally announce his retirement on Friday.
The 65-year-old former high school teacher and wrestling coach from the midwestern state of Illinois was first elected to the House in 1986. His reputation was harmed in 2006 after allegations surfaced that he and his staff failed to respond to allegations that Florida Republican Mark Foley had made inappropriate sexual advances to male House pages.
The scandal was a contributing factor in the Republicans losing control of the House in the congressional elections that year.
Some information for this report was provided by AP.