Situated near Harippad, this is a serpent shrine under the patronage of a brahmin family, headed by a priestess. The ancient shrine is an internationally renowned pilgrim centre dedicated to the Serpent God - Nagaraja. Sarpa Yakshi and Naga Yakshi are the beloved consorts of Nagaraja. It is believed that Nagaraja as the installed diety is endowed with the form of Hari (Lord Vishnu) and the spirit of Lord Shiva.
Legend has it that the first priestess of Mannarasala gave birth to a five-headed snake, which is believed to reside in the ancestral house to safeguard the family. At Mannarasala barren women are believed to be blessed with children and a special turmeric paste available at the shrine is credited with powers to cure even leprosy.