The election will see his 75-year-old successor Emmerson Mnangagwa from the ZAU-PF party face 40-year-old Nelson Chamisa from the Movement for Democratic Change (MDC) party,
Should Mr Chamisa, who is a lawyer and pastor, be victorious, he would become the nation’s youngest head of state.
Polls, which are not entirely reliable, have only given former intelligence chief Mr Mnangagwa only a slim lead over his much younger rival.
The winning candidate must secure more than 50 percent of the vote to avoid a run-off in September.
Zimbabweans will be able to start casting their votes when the polls open at 7am local time (6am BST) on Monday. They close at 7pm local time (6pm BST) later that day.
There are 23 candidates running for power but the race is likely to be a straight run between Mr Mnangagaw and lawyer Mr Chamisa.
The election will mark the first time in 38 years that Zimbabweans will not see 94-year-old Mr Mugabe’s name on their ballot paper.
Voter turnout in the presidential elections are expected to be high, with one poll by Afrobarometer indicating 85 percent of people are expected to have their say.
Mr Mnangagwa, who took over from Mr Mugabe when he was expelled from the Zanu-PF party in 2014, is the slim favourite for victory, but he has failed to impress his predecessor, who said he will not be voting for the party he headed throughout his 37-year stint in power.
But voters have also mocked Mr Chamisa for being “too young” to pose any sort of threat to the current Prime Minister.
Earlier today, Mr Mugabe said he would be voting for Zimbabwe’s opposition in the election, turning against his long-time ally.
The former President, told reporters at his mansion in Harare that Mr Mnangagwa’s Government was unconstitutional and ruled by the gun.
He said: ”I hope the choice of voting tomorrow will throw, thrust away the military government and bring us back to constitutionality.
“I said I can’t vote for those who have caused me to be in this situation, so there is Chamisa left.”
In a video on his Facebook page, Mr Mnangagwa accused his former boss of striking a deal with the opposition leader, but did not provide any evidence.
He said: “The choice is clear, you either vote for Mugabe under the guise of Chamisa or you vote for a new Zimbabwe under my leadership and ZANU-PF.”
Reacting to the former President’s earlier comments, Mr Chamisa said in a press conference: “Mr Mugabe’s wishes are his wishes.
“I am going to accept any voter with open hands. The more the merrier.”