The following are lists of candidates in the 2008 United States presidential election. Candidates who are not on any state ballots, withdrew from the race, suspended their presidential campaign, or failed to earn their party's nomination are listed separately.

Party nominees

All candidates in the table below were on the ballot in multiple states. Those who were on the ballot in enough states to win a majority in the U.S. Electoral College are marked in bold. Candidates who were on the ballot in no more than one state are listed in the next section. Ron Paul was on the ballot in Louisiana with Barry Goldwater, Jr. on the Louisiana Taxpayers Party ticket and in Montana with Michael Peroutka on the Constitution Party of Montana ticket, even though the latter is associated with the national Constitution Party. Paul's supporters also qualified him to receive write-in votes in California. Paul was no longer actively running for president when he attained ballot status and asked to be removed. His request was denied by the Montana Secretary of State, because the request was sent to him too late.

Ballot access

The two major parties in the United States, the Democratic Party and the Republican Party, had ballot access in all 50 US states and the District of Columbia. Each state sets its own requirements for candidates to gain ballot access. In some cases it is easier for party nominees to gain ballot access than for independent candidates, so Ralph Nader's independent campaign is associated with parties (pre-existing or newly formed) in some states: PF is the Peace and Freedom Party, NLP is the Natural Law Party, IEP is the Independent-Ecology Party, and IP is the Independent Party. In Kansas, Chuck Baldwin's campaign is associated with the Kansas Reform Party after a legal challenge had been brought to recognize national Reform Party candidate Ted Weill on the ballot. George Phillies appeared on the ballot in New Hampshire with the label "Libertarian", with Chris Bennett as his running mate. Notes: The tickets below were on the ballot in one state. Those without party labels are independents. Some do not have vice-presidential candidates.

Guam

Although Guam has no votes in the Electoral College, it has held a straw poll for its presidential preferences since 1980. In 2008, their ballot included Barr, McCain, and Obama. On July 10, 2008, the Guam legislature passed a law moving that poll forward to gain notoriety for Guam's election. The legislation was eventually vetoed.

Primary and convention candidates

Democratic Party primary ballot access

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Republican Party primary ballot access

and Republican Party comprehensive summary at {{legend|#FF0000|Candidate actively campaigning}} {{legend|#FFCCCC|Candidate with suspended or canceled campaign}} {{legend|white|Candidate not on ballot|border=1px solid black}}