1968 Democratic Party presidential primaries

From March to July 1968, Democratic Party voters elected delegates to the 1968 Democratic National Convention for the purpose of selecting the party's nominee for president in the upcoming election. Delegates, and the nominee they were to support at the convention, were selected through a series of primary elections, caucuses, and state party conventions. This was the last time that state primary elections formed a minority (12 states) of the selection process, as the McGovern–Fraser Commission, which issued its recommendations in time for the 1972 Democratic Party presidential primaries, would dramatically reform the nomination process to expand the use of popular primaries rather than caucuses.

After an inconclusive and tumultuous campaign focused on the Vietnam War and marred by the June assassination of Robert F. Kennedy, incumbent Vice President Hubert Humphrey was nominated at the 1968 Democratic National Convention held from August 26 to August 29, 1968, in Chicago, Illinois.

The campaign for the nomination began with incumbent President Lyndon B. Johnson expected to win re-nomination for a second consecutive election, despite low approval ratings following the Tet Offensive in January 1968. His only significant challenger was Eugene McCarthy, an anti-war Senator from Minnesota. After McCarthy nearly won the New Hampshire primary on March 12, Senator Robert F. Kennedy, another critic of the war and the brother of the late President John F. Kennedy, entered the race on March 16. On March 31, Johnson announced that he would not seek re-election. In April, Vice President Hubert H. Humphrey joined the race as the establishment candidate; he did not criticize the administration's conduct of the war and avoided the popular contests for delegates.

McCarthy and Kennedy traded primary victories while Humphrey collected delegates through the closed caucus and convention systems in place in most states.