The 2008 United States Senate election in Louisiana was held on November 4, 2008. This was the first time since the 1970s that Louisiana used primaries for federal races. Incumbent Senator Mary Landrieu won a third term by 6.39 percentage points despite being forecast as one of the most vulnerable Senate Democrats during 2008. She had received praise and wide publicity for her advocacy after Hurricane Katrina, particularly during hearings regarding FEMA's response to the disaster. This is the last time that Democrats won any statewide election in Louisiana other than Governor.

Mary Loretta Landrieu is an American entrepreneur and politician who served as a United States senator from Louisiana from 1997 to 2015. A member of the Democratic Party, Landrieu served as the Louisiana State Treasurer from 1988 to 1996, and in the Louisiana House of Representatives from 1980 to 1988.