Armenians are voting to elect a new parliament.
The Republican Party of President Serge Sarkisian and the Prosperous Armenia party - both in the governing coalition - are seen as the main contenders.
The main opposition force is the Armenian National Congress, founded by ex-President Levon Ter-Petrosyan.
President Sarkisian insisted the vote would be fair, but opposition groups have already voiced concern about irregularities.
The vote is being monitored by about 300 observers from the Organisation for Security and Co-operation in Europe.
