President Emmerson Mnangagwa, Mugabe's former ally in the ruling Zanu-PF party, faces opposition leader Nelson Chamisa of the MDC (Movement for Democratic Change) in a historic vote for the southern African nation.
The poll is a culmination of dramatic political events triggered on November 6, when then vice president Emmerson Mnangagwa (now president) was sacked by Mugabe.
On the eve of the elections, Mugabe said that he would not vote for his successor Emmerson Mnangagwa in the presidential election.
"For the first time ever we have now a long list of aspirants to power," Mugabe said at his Blue Roof private residence in Harare.
"I cannot vote for those who tormented me... I will make my choice among the other 22 (candidates) but it is a long list."
