In a statement here, party general secretary and Chief Minister J.Jayalalithaa announced P.Saroja as the party's official candidate for the by-election.
On Oct 11, DMK announced V.Maran as its candidate for the by-election.
While the Bharatiya Janata Party (BJP) has announced its decision not to contest the by-poll, the CPI-M announced its support to the AIADMK's candidate.
Meanwhile, the decision of the largest opposition party in the assembly, the DMDK continues to be in a suspense.
The by-election in the hill station, around 360 km from here, has been necessitated after sitting AIADMK legislator C.Perumal died in July. This led to the AIADMK's strength in the 235-member assembly coming down to 150. The DMDK is the second largest party in the assembly with 29, followed by the DMK with 23.
Incidentally, Saroja is the wife of Perumal.
Saroja is late AIADMK legislator C Perumal's wife
This will be the fourth assembly by-election in Tamil Nadu after the AIADMK came to power in May 2011. The ruling party won all three earlier by-elections in Pudukottai, Sankarankoil and Tiruchirapalli (West) constituencies.
According to the Election Commission's poll schedule, nominations for Yercaud by-poll could be filed Nov 9-16 and the scrutiny of the papers would be held Nov 18. The last date for withdrawal of nomination is Nov 20.
The poll is slated for Dec 4, and the vote count would be held Dec 8 -- the same date when ballots cast in the elections to five state assemblies would be counted.