Myanmardid not allow foreign media or monitors into the country for its 2010 election, which swept the army's political allies to power amid widespread complaints of cheating and intimidation.
But since taking office a year ago, President Thein Sein has carried out reforms including releasing hundreds of political prisoners, easing media restrictions and welcoming the opposition back into mainstream politics.
The election commission says about 160 foreign observers have been invited for Sunday's polls, in which pro-democracy leader Aung San Suu Kyi is standing for a seat in parliament for the first time.