Brisk polling was reported from many polling stations in Aizawl where long queues were seen in front of the booths in Mission Veng and Thakthing areas even before the elections began.
Elderly men and women were brought to the polling stations by their family members to exercise franchise in the early hours.
Chief Minister Lal Thanhawla cast his vote with his wife Lal Riliani at Zarkawt-II polling station which is in the building of Government Combined Middle School at Babutlang area in Zarkawt locality.
The Chief Minister, belonging to Congress, and all his 11 ministers are among the 142 candidates in fray.
Speaking to reporters after exercising franchise at 9:45 AM, Lal Thanhawla said he was confident of retaining power in the state.
"I have high hopes that we will retain power with a thumping majority by bagging the same number of seats (32) if not more," he said.
The people want Congress to be in power for its developmental work and running a clean government, he said.
The atmosphere in front of the polling stations was low-key and less festive due to strict diktats of the Mizoram People's Forum (MPF), the church sponsored election watchdog.
Ruling Congress and opposition Mizoram Democratic Alliance comprising MNF, Mizoram People's Conference and Maraland Democratic Alliance are contesting all the 40 seats.
Former chief minister Zoramthanga, president of the MNF was in his constituency - East Tuipui, in Mizoram-Myanmar border Champhai district and could not be contacted.
Women outnumber men by a margin of 9,806 in the electorate of 6,908,60. While there are 3,50,333 women in the electorate, male voters number 3,40,527.
Security has been tightened all along the Manipur border as also along the unfenced 64-km border near the tri-junction of Mizoram, Tripura and Bangladesh in Mamit district.
There are 1,126 polling stations in the state, of which 94 have been identified as 'critical'.