Article published on the 2010-02-07 Latest update 2010-02-07 15:25 TU
The run-off follows January's first round, which put Yanukovich ahead with a ten per cent lead. That poll was marked by widespread disillusion with the leaders of 2004's Orange Revolution and cynicism about all politicians.
The ensuing campaign has seen the pro-Western Tymoshenko accuse her opponent of wanting to "rape our democracy", while Yanukovich has said that she "delights in swimming in mud".
Both have accused the other of seeking to rig the vote, leading to predictions that a narrow win by either will lead to challenges in the courts or the streets.
Yanukovich's supporters have already erected blue tents outside the premises of the Central Elections Commission.
For all the bitterness, there is little obvious difference between the two candidates' programmes, says correspondent Gulliver Cragg. "That’s why a lot of people are saying that this election marks the end of the Orange Revolution."
The election is seen as a turn back to the east, he points out.
"The promises of taking Ukraine towards Europe and of making Ukraine a lot more democratic [...] those promises basically haven’t been kept. That’s why now Yulia Timoshenko is saying, in much the same way as Viktor Yakunokivich is, that Ukraine’s priority now needs to be to improve ties with Russia, as well as improve ties with Europe."