The political future of three union ministers - Sriprakash Jaiswal, Pradip Jain Aditya and Jitin Prasad - will also be decided by the voters that day.
Also in contention is veteran Bharatiya Janata Party leader Murli Manohar Joshi, who, having been eased out of Varanasi by prime ministerial candidate Narendra Modi, will face the electorate in Kanpur.
The other contenders include former Uttar Pradesh Congress chief Rita Bahuguna Joshi from Lucknow, and P.L. Puniya, bureaucrat-turned politician and chairman of the SC/ST Commission, who is seeking re-election from Barabanki, a seat neighbouring Lucknow.
The most watched contest will be in Rae Bareli from where the Congress chief is seeking her third consecutive term.
Busy with campaigning for the party elsewhere, her campaign is being handled by her daughter Priyanka Gandhi Vadra who has been camping in the constituency for the last one week.
Sonia Gandhi is locked in a battle with Supreme Court lawyer and activist Ajay Agarwal of the BJP, Pravesh Singh of the Bahujan Samaj Party and Archana Srivastava of the Aam Aadmi Party (AAP).
The Samajwadi Party has not fielded a candidate in Rae Bareli.
In Lucknow, the contest is between BJP chief Rajnath Singh, Abhishek Mishra, the science and technology minister in the Akhilesh Yadav government, Nakul Dubey of the BSP and Rita Bahuguna Joshi.
Joshi is currently a legislator from Lucknow Cantonment. TV artist Jaaved Jaaferi is the AAP contestant from the city.
Lucknow was represented by former prime minister Atal Bihari Vajpayee five times in the Lok Sabha.
Rajnath Singh, who is contesting from Lucknow this time, was a Lok Sabha member from Ghaziabad.
In Kanpur, the battle will be between union coal minister Jaiswal and Murli Manohar Joshi.
While Joshi initially faced hostility from local BJP leaders, things have now settled down for him.
The Samajwadi Party has fielded trader-leader Surendra Mohan Agarwal in Kanpur. Mehmood Hasan, an eye surgeon, is the AAP candidate, while the BSP has pitted Muslim leader Salim Ahmad.
The region of Bundelkhand, the impoverished and parched area of Uttar Pradesh, will also vote Wednesday.
BJP's firebrand leader Uma Bharti is contesting from Jhansi constituency. Outgoing MP Pradip Jain Aditya, Anuradha Verma (BSP), Chandrapal Singh Yadav (Samajwadi Party) and Archana Gupta (AAP) are also in the fray.
Jitin Prasad, considered close to Congress vice president Rahul Gandhi, is the party candidate from Dhaurahra.
Polling has already taken place for 33 seats in the state. A total of 33 constituencies remain, of which 15 will vote May 7, while the last 18 will go to the polls May 12.
The total number of voters Wednesday is around 24 million, of which 13 million are males and 10.9 million are females. They will vote in 25,380 polling station across the state.
Of the constituencies that will vote Wednesday, six are held by the Congress, four by the Samajwadi Party, three by the BSP and one by the BJP.
The 14 seats going to the polls are Lucknow, Rae Bareli, Kanpur, Jhansi, Hamirpur, Banda, Jalaun, Mohanlalganj, Unnao, Sitapur, Misrikh, Dhaurahra, Fatehpur and Barabanki.