The seat-sharing accord with the CPI-M was reached here at 5. a.m. under which the party, which had been allotted 12 seats, would retain most of its sitting constituencies.
CPI also signed the accord on Friday.
With this, the dissatisfaction that surfaced in the wake of AIADMK's 'unilateral' announcement of candidates for 160 constituencies seems to have dissipated.
Talks to identify seats for DMDK, second largest partner of the alliance, which would contest 41 seats, was expected to be concluded today.
It is also learnt the AIADMK is willing to accommodate the Vaiko-led MDMK by offering it 15 seats, up from nine offered earlier.
Allocation for small allies such as Manitha Neya Makkal Katchi (3 seats) actor Sarathkumar's All India Samathuva Makkal Katchi (2), All India Forward Bloc, All India Mooventhar Munnetra Kazhagam, RPI and Tamil Nadu Ilaignar Kongu Peravai (all one each) were finalised late last night.
In the 2006 Assembly elections CPI (M) contested in Chidambaram constituency but could not win. Though the party wanted constituencies such as Ambasamudram and Kovilpatti in the Southern Districts, they could get only Palayamkottai.
The polling for 234 assembly constituencies in Tamil Nadu will be held on Apr 13.