Victory looks more certain for Viktor Yanukovich.
Ukraine’s electoral commission says with 95 percent of votes counted, the pro-Russian candidate has a two point lead over presidential rival Yulia Tymoshenko.
The commission says remaining results still have to come in from Yanukovich’s strongholds, and his lead will only increase.
Prime Minister Tymoshenko is due to hold a media conference but it is not known if she will concede defeat.
Yanukovich is making a comeback after being ousted by Tymoshenko and her allies in the 2004 Orange Revolution.