The vote caps a year of growing public discontent over the lack of freedoms in the former Soviet republic and a series of deadly attacks blamed on alleged radical groups.
None of the Central Asian country's four small opposition groups can take part in the race. They said authorities rejected their requests to officially register, in order to keep them out of parliament.
All opposition-nominated independent candidates were also turned down, leaving only five legal parties - all loyal to President Islam Karimov.
Some opposition parties have urged voters to boycott the elections.
One, the Birlik party, said citizens should vote against all candidates on the ballot.
The few voters who turned up on Sunday in the first few hours of polling in the capital, Tashkent, expressed cynicism about the election.
"Probably my vote will not decide anything," said one voter, Andrei Burdin.
Another, Gennadiy Stepanov, said he did not choose any candidate on the ballot because "my vote won't change anything".
Bomb attacks killed more than
50 people earlier this year
Uzbekistan has just over 14 million eligible voters.
The Organisation for Security and Cooperation in Europe (OSCE) has sent 21 observers to monitor the poll's compliance with its standards for democratic elections.
The OSCE warned on Saturday against attempts to use its presence as a way to legitimise the vote, which it has already described as lacking fairness.
The group is expected to release a preliminary report on the election on Monday.
The predominantly Muslim nation, a key US ally in the "war on terror", has since 2001 been hosting hundreds of US troops near its border with Afghanistan.
However, the United States cut aid to the country this year due to a lack of progress on democratic and economic reforms.
President Karimov, a former Communist boss, has ruled the nation with an iron fist since 1989, and has drawn international criticism for his government's poor human rights record.
A UN envoy found after a visit in 2002 that torture was systematic in Uzbek jails. Rights groups say up to 6000 dissident Muslims are in jail for alleged religious extremism.
Uzbek Muslims opposed to the
government are persecuted
Earlier this year, more than 50 people died in bomb attacks and other assaults aimed at police, the general prosecutor's office and the embassies of Israel and the United States.
Critics say the violence was triggered by government persecution of Muslims who practise their faith outside state-run mosques.
Uzbekistan, Central Asia's most populous nation, is also one of the region's poorest and is widely viewed as having a poor business climate.
Public protests are rare in this country, where police and security personnel have extensive powers.
But last month it saw unprecedented large demonstrations against new trade restrictions, raising fears of further outbreaks of public discontent.