"Polling began at 7 a.m. with men and women queuing up in large numbers to cast their votes in the 40 assembly constituencies," said Mawia, the joint chief electoral officer of Mizoram.
Mawia said he expected the tempo of polling to increase as the day progressed. New voters and women appeared the most enthusiastic.
"I expect over 80 percent voting when polling ends at 4 p.m.," another Mizoram election department official told IANS.
At some of the polling stations, technical trouble with electronic voting machines (EVM) halted the process for brief periods.
The main poll battle is between the ruling Congress and opposition coalition Mizoram Democratic Alliance, comprising Mizo National Front (MNF), Mizoram People's Conference and Maraland Democratic Front, all regional and local parties.
Of the 40 assembly seats, 39 are reserved for tribals. One seat is for the general category.
Counting of votes will be taken up Dec 9.
The Mizoram poll was earlier scheduled for Dec 4
With the population of 10.91 lakh, Mizoram is the only state in India where women voters outnumber men by 9,806 in the total of 690,860. In all, there are 350,333 women voters against 340,527 male ones.
Altogether 1,126 polling stations have been set up across the state to hold the elections. Mizoram shares borders with Myanmar (404 km) and Bangladesh (318 km).
Of the 142 candidates, six are women, and hardly any new faces among the contestants this year.
A newly-designed device - Voter-Verified Paper Audit Trail (VVPAT), which confirms to a voter that his or her vote was cast as wished - will be used "in 10 of the 40 assembly segments of Mizoram," the official added.
This is the first time this device is being used in an election in the country.
Even though there is no major security threat from separatist outfits and Mizoram remained peaceful during the month-long electioneering, around 7,000 para-military, state and other security personnel have been deployed to ensure free and fair polls in the state.
Christian- and tribal-dominated Mizoram witnessed peaceful campaigning under the close watch of the powerful church-controlled Mizoram People's Forum (MPF), a non-government election watchdog.
Mizoram Police chief Amulya Patnaik said that during the campaigning, not a single untoward incident was reported from anywhere in the state.
The Bharatiya Janata Party, Zoram Nationalist Party and the Nationalist Congress Party are also separately contesting the state elections, fielding candidates in many seats.
Monday's vote would decide the fate of Chief Minister Lal Thanhawla, his eleven cabinet colleagues, Mizoram Women's Congress chief Tlangthanmawii and former chief minister and MNF president Zoramthanga.
Lal Thanhawla, also state Congress chief, is contesting from two constituencies -Serchhip, his home turf, and neighbouring Hrangturzo, and opposition MNF chief Zoramthanga is trying his electoral fortunes from Tuipui East, bordering Myanmar.
The Mizoram poll was earlier scheduled for Dec 4 and the counting of votes was scheduled for Dec 8.
But the ECI rescheduled the dates following the request of the church and the local political parties to allow the voters to go to church Sunday and to celebrate a local festival.
During the last assembly elections in December 2008, the Congress won 32 seats, the MNF three and the MDF one. The MPC and ZNP got two seats each.
The MNF, which ruled the state for 10 years till 2008, is the principal opposition party.