HARARE, Zimbabwe — As millions of Zimbabweans prepare to vote Monday in the most consequential election of their lives, one big question hangs in the air: Will this election — the first in 37 years in which Robert Mugabe is not on the ballot — be free and fair?

The contest pits President Emmerson Mnangagwa, 75, a former vice president often referred to as Mugabe’s enforcer because of his close relations with the army, against Nelson Chamisa, 40, the leader of the opposition MDC party. Chamisa is seeking to become Africa’s youngest head of state.

Both have promised to radically transform Zimbabwe, opening it up to the world after decades of often brutal and economically ruinous rule by Mugabe.

Past elections have been marred by campaigns of voter intimidation and outright violence. With Mugabe gone, and both candidates vowing to abide by democratic principles, there are hopes that this time it will be different.

But Mugabe’s reign left Zimbabwe deep in isolation and crisis, without a viable currency, and with massive unemployment. Zimbabweans have waited a long time for readmittance into the international community, but that is unlikely unless the election is perceived as fair.

The majority of Zimbabwe’s 5 million voters grew up under the rule of Mugabe, who resigned in November after a military takeover and pressure from the ruling ZANU-PF party that once backed him.

Supporters of the Mnangagwa and Chamisa rallied Saturday in Harare, the capital.

‘‘We have opened the country to the world,’’ Mnangagwa said Saturday, claiming that hundreds of investors had flowed into the country since he took office with billions of dollars in commitments. Many in the country have yet to see any effects, however.

Chamisa, a pastor and lawyer with little government experience, promised to defeat Mnangagwa, saying the president had done his part in helping to liberate Zimbabwe from white minority rule. ‘‘Your time is up,’’ he said. ‘‘If we miss our opportunity on Monday, we are doomed for life.’’

On the streets of the capital, many point to the ways Zimbabwe has already become freer since Mnangagwa ousted Mugabe and became president in November. For one, they can speak with journalists openly about their politics. The opposition party isn’t just tolerated but has held hundreds of rallies around the country.

But on the question of whether Zimbabwe is on the cusp of becoming a bona fide democracy, there is little agreement.

Standing under a giant billboard emblazoned with Mnangagwa’s face and the words, ‘‘The voice of the people is the voice of God,’’ Simple Siziba asked how many Chamisa billboards there were in the country.

‘‘Or let me ask you this: How many people see his face in the newspaper or hear him on the radio?’’ said Siziba, who is jobless and recycles trash for a living. He then turned to Mnangagwa, hovering above him. ‘‘And then these people want to say that it is free and fair.’’

A report compiled by Media Monitors, a Zimbabwean civil rights organization, found that 80 percent of election coverage in the state-owned newspaper was devoted to Mnangagwa and that Chamisa got just 5 percent of coverage on the state TV network.

Other Zimbabweans, going about their daily business, simply questioned the logic of Mnangagwa deposing Mugabe from power for any reason other than to retain it himself.

‘‘That is who Mnangagwa is,’’ said Pablo Nakappa, who is a bassist in a popular reggae band and an engineer specializing in the production of hydraulic seals. He alleged that even if Chamisa could win, Mnangagwa would know how to rig the election in his own favor ‘‘because he has plenty of experience with that.’’

‘‘He has brought the exact same people with him as Mugabe had. They only know one way to govern — through force,’’ said Nakappa, who said he would be supporting Chamisa’s party, the Movement for Democratic Change, or MDC.

Mnangagwa and supporters of the ZANU-PF party deny any foul play.

Mary Mahere, a resident of a rundown housing project in Mbare, a dense neighborhood of Harare, said anyone who claimed the election was unfair was just being a sore loser. ‘‘Where is the violence? There is none,’’ she said.

Reports of preelection violence have been sparse, and Monday’s voting is expected to be peaceful and orderly. But a lack of violence doesn’t necessarily mean the election is fair, observers have warned.

Local human rights organizations have documented hundreds of cases of intimidation and suspected vote-buying, and observers weren’t given access to the printing of ballot papers.

‘‘Issues related to voters’ confidence in the secrecy of the ballot, intimidation of voters, and the commitment of candidates and the military to respect a credible outcome of the vote is still concerning,’’ said Elizabeth Lewis, co-director of the US-based International Republican Institute’s observer mission.

Chamisa and other observers have said the election is already not credible. At a news conference Wednesday, he accused Zimbabwe’s independent electoral body of being an extension of ZANU-PF.

Chamisa made clear that if ZANU-PF wins the election, he will dispute the results.

‘‘Change is the will of the people,’’ he said. ‘‘And if the election does not agree with the will of the people, we will not accept it.’’