Both the governing Congress party and rival BJP have high stakes in this phase of the elections, with 35 and 23 seats from the previous election.
In the fray are Sonia Gandhi, the Congress president; her BJP counterpart Rajnath Singh; and BJP heavyweights LK Advani and Narendra Modi, Al Jazeera reported.
Among the 89 constituencies going to the polls are the political crucial Rae Bareli and Lucknow in Uttar Pradesh and Gandhinagar and Vadodara in Gujarat.
The states are Bihar, Andhra Pradesh, Gujarat, Jammu and Kashmir, Punjab, Uttar Pradesh and West Bengal.
People in two union territories - Dadra and Nagar Havelli and Daman and Diu - will also cast their votes on Wednesday as well those living in some regions of the newly declared state of Telangana.
Other big names include Farooq Abdullah, the former chief minister from Jammu & Kashmir who is locked in a war of words with Modi.
Challenging Modi in Vadodara is Madhusudan Mistry, a Congress politician, while Shankarsinh Vaghela, a veteran politician, is contesting from Sabarkantha.
Aam Admi Party, which is striving to emerge as an alternative to the BJP and Congress, has fielded candidates in 24 constituencies.
Gujarat will also have a by-election to seven Assembly constituencies on 30 April, with a total of 104 candidates.