An overwhelming 4978 delegates endorsed an amendment to the party constitution to allow Wickremesinghe to continue as party leader while 337 voted against it at the annual convention of the party held here today.
The amendment allows for elections for the party leader to be held every six years, allowing Wickremesinghe to continue for six more years.
Deputy leader Sajith Premadasa and his predecessor Karu Jayasuriya were among the delegates who voted against.
Wickremesinghe (63), who has led the UNP since the party lost power in 1994, has been at the helm of the party that has faced one election defeat after another.
He was able to form a government in 2001 as prime minister under arch rival, and then President Chandrika Kumaratunga, who later sacked his government.
Wickremesinghe, who served as prime minister twice, has held on to his position as party leader despite many challenges to oust him including a direct vote last year among party working committee members.