The Socialist prime minister, George Papandreou, requested the confidence vote last week.
While it may seem odd for a sitting government leader to jeopardize his own position by calling for a vote that could result in the need to hold new elections, the move was probably necessitated by creditor demands.
After the defections of a few members of his party, which controls 155 out of 300 seats in the Parliament, Papandreou needs to show that he still commands the loyalty of his ministers in order to credibly reassure international markets that Greece will stand by its austerity promises.
Most analysts believe that Papandreou will survive tonight's election.
Questions? Comments? Email us atNetNet@cnbc.com
Follow John on Twitter @ twitter.com/Carney
Follow NetNet on Twitter @ twitter.com/CNBCnetnet
Facebook us @ www.facebook.com/NetNetCNBC