The election is the first in the nation of 33 million since Mirziyoyev took power in late 2016 following the death of strongman Islam Karimov, who had run the former Soviet republic as a police state for 27 years.
Uzbekistan votes on Sunday in its first parliamentary election since a new leader ushered in an era of reform after years of isolation and authoritarian rule.
President Shavkat Mirziyoyev took charge of Central Asia's most populous country in 2016 after the death of hardline predecessor and former patron Islam Karimov, who had ruled for almost three decades.
Mirziyoyev has been lauded for doing away with many of Karimov's authoritarian excesses, releasing some political prisoners, battling forced labour and opening up the landlocked state to tourism and foreign investment.
But choices on the ballot in the former Soviet republic are few -- all five parties competing are represented in the outgoing parliament.
Muslim-majority but staunchly secular Uzbekistan is home to 33 million people, over 20 million of whom can vote.
The polls open at 0300 GMT (8:00 am local time) and close 12 hours later.
Britain's influential magazine The Economist this week named Uzbekistan as its country of the year, saying "no other country travelled so far" in 2019.
Yet the reform drive has so far not allowed real competition to Mirziyoyev, 62, to develop.
The 150-member lower house where no party has ever achieved a commanding majority has a long-earned rubber stamp reputation.
Currently the Liberal Democratic Party is the largest in the legislature with 52 seats, followed by Milli Tiklanish, known in English as the National Revival Democratic Party, with 36.
The People's Democratic Party, the Social Democratic Party also known as Adolat and the Ecological Movement of Uzbekistan are also represented there.
Residents of the capital Tashkent said they wanted to see more from their elected officials and voiced concerns they would not have dared express under Karimov.
Shahzod Alikulov, a builder, said the future parliament should ease the burden of the majority-rural population who feel the sharp end of energy shortages.
"For people to have gas, electricity, roads. That is what I will give my vote for," he told AFP.
The elections are being held under the slogan "New Uzbekistan, new elections" as authorities seek to brand them as the latest example of a newfound openness.
But the Organisation for Security and Cooperation in Europe (OSCE), which is sending an observer mission to the polls, has said many features of past votes remain in place.
"Very few campaign posters are visible," the group's pre-election report said.
"So far, very little evidence of outdoor campaign activities has been observed."
Karimov was often criticised by international watchdogs over torture and forced labour allegations.
Mirziyoyev has continued to honour Karimov publicly, but has been credited with eradicating much of the slavery in the country's cotton sector and lifting Uzbekistan out of isolation.
Luca Anceschi, a senior lecturer in Central Asian Studies at the University of Glasgow, said it was too early to say whether the vote holds any significance in the broader context of Uzbekistan's political transformation.
Popular participation in the poll "seems a crucial element of Mirziyoyev's strategy of support building", Anceschi told AFP.
As to whether parliament can evolve as an institution, he said, "the jury is out".