Morales did not specify what USAID had done that merited expulsion.
In the recent past, he has accused it of funding groups that have opposed his policies, specifically a lowlands indigenous federation that organized protests against a highway through a rainforest preserve.
In 2008, Morales expelled the US ambassador and agents of the US Drug Enforcement Administration for allegedly inciting the opposition.
Morales made the announcement to a crowd outside the presidential palace during an International Workers' Day rally, an occasion he has used since first taking office in 2006 for major announcements, including of nationalizations of industries.
"The United States does not lack institutions that continue to conspire, and that's why I am using this gathering to announce that we have decided to expel USAID from Bolivia," Morales told the crowd, turning to his foreign minister, David Choquehuanca and ordering him to inform the US Embassy.