Lugo said he accepted the results of Friday's vote while calling the actions an "express coup d'etat," The New York Times reported.
Vice President Federico Franco was sworn in as Paraguay's new leader.
"Today it is not Fernando Lugo who is receiving a coup, but Paraguay's history, its democracy," Lugo, 61, said.
Lugo was elected in 2008 with expectation that he would help ease anger over the disparity in landholdings. Paraguay, known as a hub for trafficking of contraband and drugs, has gone through periods of political mayhem since the dictatorship of Alfredo Stroessner ended in 1989.
The Senate voted to remove Lugo after Paraguay's lower House of Congress voted Thursday to impeach Lugo over a fight between squatters and the police this month in which 17 people were killed, the Times said.
Lugo had about a year left in his five-year term.
The Union of South American Nations, a political organization, sent a diplomatic mission to Asuncion, Paraguay's capital, and issued a statement, the Times said.
The organization said Lugo's ouster "did not respect due legal process."