"Put aside all matters and come to the polling station to cast your vote for the future of Ukraine - for Viktor Yushchenko!", the brothers said in their address posted on the boxers' website.
"At this fateful hour for Ukraine, we want to address you not only as sports fans, but also as citizens, and to appeal to your civic consciousness," the brothers' address says.
"The day of November 21 is not simply the day of the election of the President of Ukraine. It is the Day of choice for Ukraine," the brothers also noted.
"This is the Day that our people have been moving toward for more than a thousand years: through the Tatar-Mongol invasion; through Lithuanian-Polish enslavement; through the arbitrariness of the monarchy; through the bloody and famine-stricken twentieth century."
The Klitschko brothers' address ends with the words "We believe in Victory!"
The address also quotes an excerpt from Taras Shevchenko's poem "Both the Dead and the Living and the Unborn":
"...Ukraine has struggled To the very edge: Worse than a Pole, her own children Crucify her..."