People in Bahrain are set to elect representatives for the lower house of parliament, the third such vote since it became a constitutional monarchy.
Correspondents say the main contest is between Islamists and those with a more secular vision for the Gulf state.
The election comes amid rising tension between the dominant Sunni Muslim community and majority Shia Muslims.
The government has also been criticised for arresting dissidents and curtailing media and internet freedom.
Observers will also be watching to see if Bahrain's only woman in parliament is joined by other female MPs.
Although women got the right to vote in 2001, strong discrimination against their participation in Bahraini politics still exists. The main Islamist parties are unwilling to back women candidates.
BBC News
