The 2000 United States Senate election in Pennsylvania was held on November 7, 2000. Incumbent Republican U.S. Senator Rick Santorum won re-election to a second term. As of 2019, this is the last time the Republicans have won the Class 1 Senate Seat from Pennsylvania.
Santorum had gained a reputation as a polarizing figure during his first term in the Senate, but he entered the race with a large fundraising advantage and high levels of support from the political right. The contest began for Democrats with a brutal primary challenge; U.S. Congressman Klink narrowly bested State Senator Allyson Schwartz and former Lieutenant Governor nominee Tom Foley by portraying himself as the only candidate who could defeat Santorum. Klink was viewed as a viable choice because he was a traditional Democrat on most issues and had strong union ties but also was pro-life, which Democrats hoped would return votes to their party in the heavily Catholic but economically liberal coal regions of the state. However, enthusiasm around Klink's campaign quickly waned. Liberal Democrats balked at donating to a candidate who was almost as socially conservative as Santorum. This was especially true in Philadelphia, where Klink was all but unknown. Klink was also badly outspent, leaving him unable to expand his presence in the state; he didn't run a single ad on Philadelphia television. Santorum, in contrast, successfully balanced his national recognition on social issues with local concerns en route to a surprisingly large victory. Ultimately, Klink only carried eight counties.