Balloting is being held for 10 Lok Sabha seats and one assembly constituency.
Poll officials said over 42 percent of the electorate cast ballots in the first seven hours of polling. The process was expected to gain momentum as the day progressed.
At three polling booths voters effected a poll boycott, but the issue was later resolved.
The parliamentary constituencies where voting is taking place are Vidisha, Dewas, Ujjain, Indore, Dhar, Ratlam, Mandsaur, Khargone, Khandwa and Betul.
As many as 118 candidates are in the fray for the 10 Lok Sabha seats while 11 are battling for victory in the Vidisha assembly bypoll.
In Vidisha, the Bharatiya Janata Party’s Leader of Opposition in the Lok Sabha, Sushma Swaraj, is pitted against Congress candidate Lakshman Singh, the younger brother of Congress general secretary Digvijaya Singh.
For the Indore seat, the BJP has fielded Sumitra Mahajan who is contesting against Satyanarayan Patel of the Congress and Anil Trivedi of the Aam Aadmi Party.
Other prominent candidates include former union minister and Congress leader Kantilal Bhuriya in Ratlam and Congress candidate Meenakshi Natarajan in Mandsaur.
Nine electronic voting machines were changed following glitches.
In the first four hours, Dewas recorded 30.11 percent turnout and Dhar 19.2 percent. The average footfalls of electorates across the state was 22 percent.
A total 46,133 electronic voting machines (EVMs) are being used at 19,444 polling booths with 155,552 officials on poll duty.
As many as 16,960,213 electors, including 8,171,532 women, are eligible to exercise their franchise.
Tight security arrangements have been made and police and paramilitary forces have been deployed for peaceful polls.
Balloting started at 7 a.m. and is slated to finish at 6 p.m.
This is the third and final round of polling in the state. The first two phases saw voting in 19 constituencies.
Of the 10 constituencies where voting is being held Thursday, the Congress had won six in the 2009 Lok Sabha elections.