The move by the National League for Democracy, the country's key opposition party, would seriously undermine the credibility of any polling in the eyes of foreign governments, which have urged the junta to ensure all groups take part in the elections.
New election laws required political parties to register before the first week in May. Parties that do not register will not be able to participate in this year's election and will cease to exist, under rules enacted this month by the military government that also bar Suu Kyi from participating in the polls.
Even before the official decision, party spokesman Nyan Win indicated the party would decide not to register. Asked if that would marginalise the party, he said, "We will continue to exist politically by not registering. If we register, we will only have a name void of all political essence."
"We will survive as long as we have public support," Nyan Win said.
Security was heightened, with plainclothes police and pro-government security guards stationed around the party's compound as the delegates met Monday in Yangon.
"This meeting is a life-or-death issue. If we don't register, we will not have a party and we will be without legs and limbs," said Win Tin, a veteran party member and one of Myanmar's longest-serving political prisoners, having spent 19 years behind bars before his release in 2008.
He said the journey ahead would be difficult if the party chooses to opt out of elections but that its members could still maintain their democratic principles and spirit.
Last week, Suu Kyi was quoted by her lawyer as saying she opposed registering her party because the ruling junta's restrictions on the vote were "unjust". But she stressed she would let the party decide for itself.
The party won the last election held in Myanmar in 1990 by a landslide but was barred by the military from taking power.Suu Kyi is under house arrest and the new election laws effectively bar her from running and voting. One law also instructs political parties to expel members convicted of crimes or face de-registration