The key contestants for the Lok Sabha are union Ministers S. Jaipal Reddy, Sarve Satyanarayana and Balram Naik, Telangana Rashtra Samithi chief K. Chandrasekhara Rao, Lok Satta Party chief Jayaprakash Narayan and Majlis Ittehadul Muslimeen (MIM) president Asaduddin Owaisi.
Telangana will formally become a state on June 2.
The main contenders for the assembly seats include Chandrasekhara Rao, Congress's Telangana unit president Ponnala Lakshmaiah, working president Uttam Kumar Reddy, former deputy chief minister Damodar Rajanarasimha, and former state ministers Geeta Reddy and D. Sridhar Babu.
Balloting is taking place at 30,574 polling booths.
As many as 265 candidates are in the fray for the Lok Sabha and 1,669 for the assembly seats.
More than 28.17 million electors are eligible to exercise their franchise.