Cepeda lost by one percentage point to his opponent, right-wing politician Abelardo de la Espriella, who received the support of U.S. President Donald Trump.
The election victory for de la Espriella, a businessman and lawyer, was secured by a margin of almost 251,000 votes.
Iván Cepeda and outgoing President Gustavo Petro initially did not accept the vote count; Cepeda said he wanted to wait for a review of the election results. But on Wednesday, Cepeda finally announced that he was conceding defeat.
