Security is tight in view of the poll boycott call by the banned All Tripura Tiger Force.
Voters lined up as the polling began at 0700 IST and there was no report of violence from any part of the state.
Elections are being held in East Tripura and West Tripura constituencies, where 1,976,503 voters will exercise their franchise to choose from 12 candidates.
Special security measures have been taken in 150 booths located in insurgency-prone areas, which will be aerially monitored, Director General of Police G M Srivastav said.
Border outposts in the state are on high alert.