In all, 13 candidates are vying to become the country's fifth head of state since Slovakia gained independence in 1993 after Czechoslovakia split in two. Andrej Kiska, a successful businessman-turned-philanthropist, is not standing for a second five-year term in the largely ceremonial post.
His term in office was marked by clashes with former prime minister Robert Fico, considered a populist leader. Kiska supported the huge street protests that led to the fall of Fico's coalition government amid a political crisis triggered by the slayings last year of an investigative reporter and his fiancee. The reporter, Jan Kuciak, was investigating possible widespread government corruption and Italian mob influence.
If no single candidate wins a majority on Saturday, a runoff will be held on March 30 in this central European nation of 5.4 million people.
WHAT'S AT STAKE
The president has the power to pick the prime minister, appoint Constitutional Court judges and veto laws. Parliament can override the veto with a simple majority, however. The government, led by the prime minister, possesses most executive powers.
Caputova, a 45-year-old lawyer, is a rising star of Slovak politics. She became known for leading a successful fight against a toxic waste dump in her home town of Pezinok near the capital of Bratislava, for which she received an international environmental prize in 2016. She was also part of a campaign in 2017 that led to the annulment of pardons granted by former authoritarian prime minister Vladimir Meciar. She is deputy chairman of "Progressive Slovakia," a non-parliamentary party that supported the massive street protests after Kuciak's death.
A career diplomat, 52-year-old Sefcovic was a member of the Communist Party before the anti-Communist 1989 Velvet Revolution. Sefcovic accepted an offer to stand from Fico's left-wing Smer-Social Democracy party, a dominant political group in Slovakia in recent years whose reputation has been tarnished by corruption scandals.
OTHER NOTABLE CANDIDATES
A former justice minister and chief judge of the Supreme Court, 61-year-old Harabin was a close ally of Meciar, whose rule in the 1990s was marred by repeated flouting of the law. A populist, Harabin exploits the fear of migration and presents himself as a guardian of traditional conservative values. As a vocal opponent of the sanctions against Russia for its actions against Ukraine, Harabin is a favorite candidate of pro-Russian media.
Marian Kotleba, 42
The 42-year-old heads the neo-Nazi People's Party Our Slovakia, which has 14 lawmakers in the 150-seat Slovak Parliament. Kotleba and his party speak admiringly of Slovakia's time as a Nazi puppet state during World War II. Party members use Nazi salutes and consider NATO a terror group. They want Slovakia to leave the military alliance and the European Union.
Caputova and Sefcovic are predicted by polls to be the two candidates to advance to a runoff. But the last polls allowed were published two weeks before Saturday's ballot. Analysts say there's a room for a surprise result, particularly for Harabin who was running third in the polls.