The bypoll in Medak parliamentary seat was necessitated due to the resignation of TRS President K Chandrasekhar Rao after he became the Chief Minister.
The ruling TRS has fielded K Prabhakar Reddy as its candidate, while main opposition Congress' candidate is former minister V Sunita Laxma Reddy.
Former Congress MLA T Jayaprakash Reddy is the nominee of the BJP-TDP combine.
The by-election in Nandigama (SC) Assembly segment in Krishna district of Andhra Pradesh was caused by the death of TDP MLA T Prabhakar due to heart attack days after his election. His daughter T Soumya is the ruling TDP candidate.
The result in Nandigama (SC) Assembly constituency as well as Medak Lok Sabha seat are expected by the afternoon.
Security has been made heightened for counting of votes in both the places.