By-elections to two state assembly constituencies were held in Tamil Nadu, India, in two separate phases.

The election results were not expected to change the prospects of the party in power, the Dravida Munnetra Kazhagam (DMK), and its Chief Minister M. Karunanidhi.

Both phases of this by-election resulted in a big victory for DMK and Indian National Congress, who were part of the Democratic Progressive Alliance.

The election for Thirumangalam was held on 9 January and for Bargur, Thondamuthur, Ilaiyangudi, Cumbum, and Srivaikuntam constituencies on 18 August.

The election results were not expected to change the prospects of the party in power, the DMK, and its Chief Minister M. Karunanidhi.

Citing concerns of the governance of M. Karunanidhi, and the alienation of his allies, they decided not to support anyone or participate in this by-election.

[8] AIADMK general secretary J. Jayalalitha cited unreliability of Electronic voting machines as the reason for the poll boycott.

[9] Tamil Nadu Congress party leader K. V. Thangabalu said that ADMK chose not to contest polls for fear of losing them.

The seat fell vacant when the sitting member M. Kannappan resigned after switching parties from MDMK to DMK.

The candidates included N. Ramakrishnan of Dravida Munnetra Kazhagam, M. Sasikumar of Bharatiya Janata Party, K. Rajappan of Communist Party of India (Marxist), R. Arun Kumar of Desiya Murpokku Dravidar Kazhagam and G. Ramaraj of Uzhaippali Makkal Katchi.

On 23 November, the Pattali Makkal Katchi (PMK), who are not in alliance with either DMK or AIADMK, will only contest if the current Chief Minister M. Karunanidhi, ensures the election is run in a fair manner.

[28] The election was necessitated after the previous winner S. P. Jayaraman, representing DMK, died earlier this month.

The election was necessitated after the resignation previous winner Anitha R. Radhakrishnan, due to the fact that he switched from AIADMK to DMK.