The 2008 United States Senate election in Delaware was held on November 4, 2008. Incumbent Senator Joe Biden, who was also the Democratic nominee for vice president in the concurrent presidential election, faced Christine O'Donnell in the general election. Biden won re-election to a seventh term with 64.69% of the vote, his best-performing result in his senatorial career, while also being elected vice president. Biden took his oath of office in the Senate chamber with the rest of his colleagues on January 3, 2009, but resigned his seat on January 15, 2009, and assumed the vice presidency five days later. Delaware Governor Ruth Ann Minner appointed Ted Kaufman, a Democrat and longtime Biden advisor, to fill the vacant seat pending a 2010 special election in which O'Donnell once again ran unsuccessfully for the seat, losing to Democrat Chris Coons.

Joseph Robinette Biden Jr. is an American politician who is the 46th and current president of the United States since 2021. A member of the Democratic Party, he previously served as the 47th vice president from 2009 to 2017 under President Barack Obama and represented Delaware in the United States Senate from 1973 to 2009.