An electorate of 17,40,576, including 8,82,236 woman voters, are eligible to exercise their franchise to choose their representatives from among 279 candidates in the 10th assembly polls.
A total of 12,967 polling personnel have been deployed to conduct the elections which began at 7 am and would continue till 4 pm.
Chief Minister O Ibobi Singh cast his vote at a polling station in Khangabok of Thoubal district, officials said.
Around 350 companies of security personnel including 270 central para military forces were deployed besides the state armed police.
Prominent candidates whose fate would be sealed on Saturday include the Chief Minister who is contesting from Thoubal constituency, former vice chancellor of Manipur university Ng Bijoy (Khurai) and Forest Minister Th Debendra (Jiribam).
Manipur has nine districts - Imphal East, Imphal West, Bishnnupur and Thoubal (all in valley) and Churachandpur, Ukhrul, Senapati, Tamenglong and Chandel in the hills.
Security forces are keeping a tab on the situation in the state, where blasts have taken place in the past few days, amid reports that insurgent groups might target some candidates.