Polling began at 7 am and will end at 3 pm, the Election Commission (EC) said.
An electorate of 19,02,562 comprising 9,28,573 male and 9,73,989 female voters will decide the fate of 168 candidates. The number of new voters is 45,642.
Of the total 1,643 polling station where polling is being held, the EC has identified 837 polling stations as hyper sensitive and 529 as sensitive.
For maintaining peaceful polling 280 companies of central paramilitary forces and armed police of other states have been deployed.
The rest of the security forces will be deployed in the polling stations, the EC said adding that Manipur Police will not be be deployed in them.
In the first phase prominent political figures of the state like Speaker Th Lokeswar Singh, ministers I Hemochandra Singh, Govindas Konthoujam, Kh Ratankumar Singh and T Manga Vaiphei, Manipur PCC President T N Haokip, former ministers Phungzathang Tonsing, and Y Erabot Singh and BJP leader Th Chaoba Singh are in the election fray, the EC said.