joined the AIADMK in the presence of party General Secretary and Tamil Nadu Chief Minister J Jayalalithaa.
Ramadoss called on Jayalalithaa and joined the party by receiving the primary membership card from her, a party release said here.
He emerged victorious in the 2004 Lok Sabha polls and lost to V Narayanasamy of Congress in 2009. He resigned from PMK then and took up an academician's post in Puducherry.
Ramadoss had contested the April 24 LS polls this year as an independent, but lost.