The 2004 Elections for the Pennsylvania House of Representatives were held on November 2, 2004, with all districts being contested. Necessary primary elections were held on April 27, 2004. Necessary primary elections were held on May 21, 2002. The term of office for those elected in 2004 ran from January 4, 2005 through November 2006. State Representatives are elected for two-year terms, with the entire House of Representatives up for a vote every two years.
A special election for the 99th legislative district was held on March 18, 2003 following the December 2002 death of Leroy M. Zimmerman. Republican Gordon Denlinger easily defeated Democrat Bernadette C. Johnson to keep the seat in Republican hands.
A special election for the 168th legislative district was held on June 17, 2003 following the March 2003 death of Matthew J. Ryan. Republican Tom Killion easily defeated Democrat William A. Thomas to keep the seat in Republican hands.
A special election for the 44th legislative district was held on June 17, 2003 following the election of John Pippy to the Pennsylvania Senate. Republican Mark Mustio defeated Democrat Frederich Liechti to keep the seat in Republican hands.
A special election for the 3rd legislative district was held on July 22, 2003 following the May 2003 death of Karl Boyes. Republican Matthew W. Good easily defeated Democrat Brian C. McGrath to take the seat.
A special election for the 109th legislative district was held on January 27, 2004 following the election of John Gordner to the Pennsylvania Senate. Republican David R. Millard defeated Democrat Paul Reichart to keep the seat in Republican hands.