Senator Bernie Sanders suspended his campaign to become President of the United States, ABC News correspondent reported.
This development paves the way for former Vice President Joe Biden to become the Democrats Party's candidate.
Sanders, 78, told campaign staff of his decision during a conference call on Wednesday before addressing his supporters online.
A self-described Democratic socialist, Mr Sanders found early success making healthcare and working-class issues a key part of his election platform.
"We have transformed American consciousness as to what kind of nation we can become and have taken this country a major step forward in the never-ending struggle for economic justice, social justice, racial justice and environmental justice," Mr Sanders told supporters in a live stream.