Election officials said they were "not capable" of holding the vote in areas of northern Shan and Kachin states bordering China because of the ongoing fighting.
The move had been anticipated and mainly affects areas battered by war or beyond the government's writ, in a country where several ethnic minority armies still resist control by the state.
"Some village areas have security restrictions and we have security concerns about those. Others are in the control of Kachin (rebels) where we are not capable of holding elections," Tun Aung Khaing, a senior election official in Kachin State, told AFP.
In addition, five townships will not hold polls on Nov 8 in the semi-autonomous areas of the ethnic Wa group, who had already vowed not to allow the elections on their territory in Shan state.
In Kachin, the decision affects nearly twice as large an area as a similar cancellation ahead of 2010 polls, where elections were called off due to pockets of unrest.
The move comes as Myanmar prepares to sign a limited ceasefire on October 15 as it tries to end decades of fighting before elections.
Aung San Suu Kyi's opposition is expected to make major gains in Myanmar's general election, the first in a quarter of a century that her party is participating in.
She is not expected to attend the ceasefire signing, which
is between the government and eight armed groups. The deal is being shunned by several major insurgent groups, including some based in Kachin and Shan states.
Clashes between the government and KIA have intensified in
recent weeks, while fighting continues in northern Shan state.
The government today rewarded those signing Thursday's ceasefire by removing them from its list of banned organisations.
