Across 49 seats in North 24 Parganas, Bidhannagar and Howrah district, a total of 1.08 crore voters will exercise their franchise in about 12,500 polling stations from 7 AM to 6 PM.
Voters will have 345 candidates, including a number of Trinamool ministers like Amit Mitra, Purnendu Basu, Chandrima Bhattacharya, Bratya Basu, Jyotipriyo Mullick and Aroop Roy to choose from.
Out of them, only 40 candidates are women.
Following reports of violence in the third phase of West Bengal Assembly elections which left at least one CPI-M worker dead, the Election Commission has made unprecedented security arrangements for this phase.
Altogether, 90,000 security personnel including central armed forces have been deployed to ensure free and fair elections. Special intervention includes patrolling at night and even on river, which is being done for the first time in this election.
In the fourth phase of West Bengal Assembly elections special focus is being laid on the Salt Lake area in the city, EC officials said.
The central force contingent includes 672 companies who will be assisted by 22,000 strong state police team.
Route marches for area domination by security forces, which normally begin after the campaign ends, started two nights ago.
Besides one police observer in each of the districts, two more have been deployed in North 24 Parganas and another one in Howrah.
All eyes will be on former state transport and sports minister Madan Mitra, who is contesting from Kamarhati seat in North 24 Parganas district from Alipore jail.
Madan Mitra was arrested by CBI in December 2014 in the multi-crore Saradha chit fund scam case.
This is the first time that a high-profile candidate is fighting elections in West Bengal from jail.
TMC supremo and Chief Minister Mamata Banerjee campaigned for Mitra in his constituency saying he has been a victim of a conspiracy by the Centre.
Mitra's name has also figured in the Narada sting operation, an issue which has been haunting the TMC ever since the video tapes were released.