Ukrainians vote on Sunday to vote in the first round of the presidential election Petro Poroshenko seeks re-election, but the surprise leader is comedian Volodymyr Zelenskiy ,
Both candidates and former Prime Minister Yulia Tymoshenko expressed largely pro-European views during the election campaigns.
Candidates are considered serious contenders.
If no candidate reaches more than 50% on Sunday, the two best will be played in a second round on April 21
A total of 39 candidates are on the ballot. However, it is believed that only the top three have a chance of winning.
The Ukrainian president has significant powers in security, defense and foreign affairs, and the system of the former Soviet republic is called a semi-presidency.  Media playback is not supported on your device.
Mr. Poroshenko, one of the richest oligarchs of Ukraine, was elected after a former pro-Russian president Viktor Yanukovych was overthrown in the Maidan revolution in February 2014 followed from the annexation of Crimea by Russia and an uprising that was supported by Russia.
The next president will inherit a deadlocked conflict between Ukrainian troops and Russian-backed separatists in the east While Ukraine is trying to meet EU requirements for closer economic relations.
The EU states that about 12% of the 44 million people in Ukraine are deprived of their rights, mainly those living in Russia and the Crimea, which Russia annexed in March 2014.  Separately controlled areas boycott the election.
Who are the main candidates?
The 41-year-old Zelenskiy wants to shoot his satirical television program in which he portrays an ordinary citizen who becomes president after fighting corruption – into reality.
He has a choice of around 25% and is considered attractive to younger voters. His campaign has used social media extensively.
President Poroshenko, 53, wants to appeal to conservative Ukrainians with his slogan "Army, Language, Faith".
He says his support for the military has helped to keep the separatists in eastern Ukraine in check. He has also negotiated an association agreement with the EU, which also includes visa-free entry of Ukrainians. During his tenure, the Ukrainian Orthodox Church became independent of Russian control.
However, his campaign was followed by allegations of corruption, including a defense procurement scandal that erupted last month.
According to opinion polls, Yulia Tymoshenko (58), who ran for prime minister in 2010 and 2014. She played a leading role in the Orange Revolution of 2004, Ukraine's first major step to ally with the EU.
The front-runner among pro-Russian candidates, Yuriy Boyko, says he "normalizes" relations with Russia.