Egyptian authorities have urged the electorate to take part in the vote, although it remains to be seen just how high the turnout will be.
President Sisi, a former military commander, faces just one challenger, a not-so-well-known politician, who is expected to barely register against the incumbent.
Critics have slammed the election as a charade after more serious challengers were forced to quit the race.
Egyptian authorities hope that three days of voting will be enough to produce a decent turnout for Sisi. The president still has some supporters, although his austerity measures, and a fierce security crackdown have eroded much of his support.
Ironically, President Sisi says he would have liked to see more candidates running, seemingly oblivious of the fact that his own government has prevented all his main political challengers and rivals from competing in this election.
Polls opened on Monday, with those who cast ballots saying they were voting for stability.
Sisi, an ex-general who in 2013 led a military coup, and ousted Egypt’s first democratically elected president, Mohammad Morsi of the Muslim Brotherhood, is trying to defeat insurgents in the Sinai Peninsula, as well as complete a series of mega-projects inaugurated amid great fanfare.
Sisi has said he will not seek a third term in office, but few believe that, and virtually all his critics expect him to remove a two-presidential term limit.
Sisi won nearly 97 percent of the vote in 2014, but less than half of eligible Egyptians took part in the vote, even though the election was extended to three days.
