Reportedly, she has defeated her rival CPI candidate C Mahendran by one lakh fifty thousands votes.
Jayalalithaa polled 160,432 votes while her nearest rival, Communist Party of India's (CPI) C. Mahendran, got just 9,710 votes. The total electorate in the constituency was around 245,000, and the chief minister bagged more than 50 percent of that.
As noisy celebrations erupted at the AIADMK headquarters and outside Jayalalithaa's residence, Tamil Nadu Governor K. Rosaiah congratulated her over her landslide win, an official statement said.
AIADMK activists and leaders generously distributed sweets to all and sundry and burst crackers to celebrate the thumping victory -- a record of sorts for Jayalalithaa.
An elated Jayalalithaa thanked voters and AIADMK supporters for her massive victory and said the result was a forerunner for the 2016 assembly elections.
This is the seventh by-poll victory for AIADMK since it came to power in 2011. The party has won all the by-polls held since 2011.
In 2006, AIADMK's P.K. Sekarbabu polled 84,462 votes in Radhakrishnan Nagar. In 2011, P. Vetrivel of AIADMK got 83,777 votes and defeated Sekarbabu, who by then was in the DMK. Vetrivel's victory margin was over 31,000 votes.
This time the polling percentage was higher at around 74 percent, up form 72.72 percent in 2011.
While there were 28 candidates in the fray, only CPI's Mahendran was viewed as a serious opponent for Jayalalithaa.
Major opposition parties like the DMK, the PMK, the DMDK, the Congress, the BJP and the MDMK stayed away from the contest.
The two Left parties - CPI and CPI-M - fielded Mahendran as their joint candidate.
However, going by the votes polled by Jayalalithaa, it is clear the vote banks of the opposition parties fell into Jayalalithaa's kitty and did not go to the CPI candidate.
Why by-election was held
The by-election was necessitated following AIADMK's P Vetrivel vacating the seat in May, apparently to enable Jayalalithaa seek re-election. She has to fulfil the constitutional requirement of getting elected as MLA within six months of becoming Chief Minister.
Earlier, party supporters said today's trends were a 'precursor' to the assembly polls scheduled next year. During her campaign on June 22 at RK Nagar, Jayalalithaa had not only sought a massive victory for her party, but insisted that it should be a 'precursor' to the next Assembly polls.
Referring to her conviction in a disproportionate assets case, in which she was subsequently acquitted, Jayalalithaa had said that there was a situation where she had to step aside as Chief Minister due to a 'politically motivated case,' while insisting that the June 27 bypoll on this constituency was a "compulsion".
Jayalalithaa had returned as the Chief Minister of the State on May 23 after being acquitted in the disproportionate assets case by the Karnataka High Court. She had been convicted in the case in September last by a trial court in Bengaluru.
(With inputs from PTI)