The city constituency, which had witnessed 72.72 percent voting in the 2011 Assembly elections, had registered 63 per cent voting till 4 PM.
While 74.8 per cent of the female voters exercised their franchise, the figure for male stood at 74 per cent today.
Brisk polling was reported throughout the day as serpentine queues were seen in a cross-section of polling stations right from the time the voting commenced.
Armed personnel were on guard at the polling booths, even as Election Commission had identified 22 of the 230 polling stations as vulnerable.
It had implemented a series of measures including deployment of static surveillance teams, micro observers and flying squads to ensure fair and peaceful polling and the process was recorded and monitored using laptops with internet connectivity.
CPI, AIADMK's main rival in this bypoll, alleged booth- capturing. The party's candidate C Mahendran said that a complaint had been filed with election authorities alleging that some of the booths were captured by AIADMK men at the fag end of polling.
The ballot boxes will now be stored in a strong room at a designated centre amidst tight security and opened for counting of votes on June 30. Besides Jayalalithaa and Mahendran, 26 others, including maverick social activist 'Traffic' Ramaswamy alias KR Ramaswamy, are in fray for the byelection which comes a year ahead of the Assembly polls.
Main opposition parties--DMK, DMDK, Congress, BJP and PMK-- have boycotted the bypoll. One of the smallest constituencies in Tamil Nadu, RK Nagar has 1,20,210 men voters and 1,23,014 women voters and 77 voters of the other category, the third gender.
The by-election was necessitated by AIADMK's P Vetrivel vacating the seat in May to enable Jayalalithaa seek re-election post her acquittal by the Karnataka High Court in a graft case.
Jayalalithaa has to fulfill the constitutional requirement of getting elected as MLA within six months of becoming Chief Minister.
The AIADMK supremo had returned to the top post on May 23 after being acquitted in the case. She had been convicted in the case in September last by a trial court in Bengaluru.