Elections for the Pennsylvania State Senate were held on November 2, 2004, with even-numbered districts being contested.

[2] The term of office for those elected in 2004 will run from January 4, 2005[3] through November 2008.

[citation needed] Necessary primary elections were held on April 27, 2004.

[4] Bob Regola, a Republican member of the Hempfield Township Board of Supervisors, defeated Democratic senator Allen G. Kukovich in the 39th senatorial district.

Republican State Representative Pat Vance succeeded the retiring Republican Senator Harold F. Mowrey, Jr. Four senators who won special elections prior to the 2004 election, Dominic F. Pileggi, Connie Williams, John R. Gordner, and John Pippy, each won full terms.