Hugo Martinez from the left-wing Farabundo Marti National Liberation Front (FMLN); businessman Carlos Calleja from the right-wing Nationalist Republican Alliance (ARENA); former mayor of the country's capital, Nayib Bukele from the conservative Grand Alliance for National Unity (GANA); and Josue Alvarado from the centrist Vamos party are running for presidency.
Incumbent President Salvador Sanchez Ceren cannot run for a second consecutive term under the country's legislation.
Around 1,600 polling stations will be open from 7 a.m. to 5 p.m. local time (from 13:00 to 23:00 GMT). Over 5.2 millions citizens have registered to vote. Security measures will be enhanced, with the country's police, Armed Forces, and prosecution being in charge of it.
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To win in the first round, a candidate must secure over 50 percent of the vote. Otherwise, a run-off will be held on 10 March, with two top candidates facing each other. In El Salvador, the president is elected for a five-year period.
Bukele is reportedly an active social media user who wants to modernize the local government, introduce infrastructure projects and push reforms to tackle country's economic issues.
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Bukele has studied law at Jose Simeon Canas Central American University but reportedly left before getting a degree.
El Salvador's last six presidents have come from either ARENA or FMLN parties.