Honduras looks set to elect its first female president, Xiomara Castro, after the ruling party conceded defeat.
Ms Castro, the candidate for the left-wing Libre (Free) Party, has a preliminary lead of almost 20 percentage points over her rival.
Her victory will bring an end to the 12-year reign of the right-wing National Party, which has been plagued by scandals and corruption accusations.
Ms Castro will replace the divisive President Juan Orlando Hernández.
He has been dogged by allegations of ties to the drugs trade after his brother Antonio was jailed for trafficking in the United States.
Ms Castro has promised to "pull Honduras out of the abyss" of "a narco-dictatorship and corruption".