The Keezhperumpallam temple is dedicated to Lord Kethu though Lord Shiva and goddess Parvathi are also worshipped in the forms of Naganathaswamy and Soundaranayagi respectively in the temple.
Since Lord Ketu is the presiding deity at the temple, there is an idol of God depicting him as half man and half snake. People affected by inappropriate position of Ketu in their astrological charts, throng to the temple for riddance from this dosha.
It is believed that the temple was constructed in 12th century A.D. by the Chola Kings who were great devotees of Lord Shiva. Today, the temple is an important pilgrim center for the people of Tamil Nadu and great saints like Sundarar, Appar and Sambandhar have sung songs in praise of the temple.
According to a local legend, there is an underground tunnel that connects the temple at Keezhperumpallam with the Brihadeeswara temple at Thanjavur. However, no traces of the tunnel have been found despite repeated diggings.