Chief Minister Siddaramaiah has played for high stakes in the polls that was marked by a no-holds barred attack by leaders of Congress and JDS, which has the backing of BJP for both the seats.
The bypoll was necessitated by the resignation of N Cheluvarayaswamy (Mandya) and former Chief Minister H D Kumaraswamy (Bangalore Rural) who quit after being elected to the Assembly in May.
Karnataka Chief Electoral Officer Anil Kumar Jha said about sixty teams of surveillance and flying squads would be deployed for the by-elections.
Polling will begin at 8 am and end at 5 pm, he said.
More From This Section
He said about 36.37 lakh voters in both parliamentary constituencies were expected to vote in 4,360 polling booths.
The Gowda belt of Mandya is a stronghold of JDS, which won five of the eight Assembly seats in the district in the May elections.
In Bangalore Rural, where Kumaraswamy had won by 1.3 lakh votes in the 2009 Lok Sabha polls, the Congress has secured the support of Samajwadi Party MLA, C P Yogeeshwara, who who reigned supreme in Channapa Assembly segment defeating Anita in May.