A close contest is expected between Begum Kulsoom Nawaz, wife of former prime minister Nawaz Sharif, and Pakistan Tehreek-e-Insaf (PTI) candidate Dr Yasmin Rashid.
In a massive setback to Nawaz Sharif, the Pakistan Supreme Court on Friday dismissed the review petitions filed by the deposed Prime Minister and his children against the July 28 Panama Papers judgement.
According to the ECP's code of conduct, members of the national and provincial assemblies are barred from engaging in political activities in the NA-120 constituency ahead of the by-poll.
The polling will start at 8 am and conclude at 5 pm without any break.
Carrying the election symbol of "lion", Begum Kalsoom Nawaz is in the run for the PML-N while Dr Yasmeen Rashid is running for the PTI with the symbol of "bat".
"For the first time in the history of Pakistan, Biometric Voter Verification Machines are also being tested in the Constituency".
The ECP said a total of 350,000 ballot papers are being printed for the by-poll, where 324,786 voters are registered to cast their vote.
Tight security through Army, Rangers and the police has been ensured in the constituency while CCTV cameras are also fixed where necessary.
Talking to reporters outside the court, Pakistan Muslim League-Nawaz leader and Minister for Information Technology Anusha Rahman said the court's decision was a "disappointment" for her party.
Kulsoom is in London where she is undergoing treatment for her throat cancer.
Election Commission of Pakistan (ECP) has finalized all arrangements to hold bye-election in NA-120 Lahore-III in a free, fair, transparent and peaceful manner on Sunday. She led rallies, held public meetings and conventions where she received big public response.
Surprisingly, no candidate of three leading parties has their vote registered in the constituency NA-120 for which they are contesting.