Ramanathaswamy temple is known for its imposing structure, majestic towers, intricate sculptural  works and corridors, making it an architectural marvel. The main deity worshipped in the temple is in the form of lingam. There is also an idol of Nandi, which is a massive statue, about 17.5 feet tall. Other deities worshipped here include Goddess Vishalakshi, Parvathavardhini, Lord Vinayaka and Lord Subrahmanya, Utsava idol, Sayanagriha and Perumal.

The legend behind the temple is associated with Lord Rama from the Indian epic Ramayana. It is believed that Lord Rama, after defeating the demon king Ravana, wanted to worship Lord Shiva as part of atonement. He asks Hanuman to bring him a Linga from Kashi. When Hanuman delayed his return, Goddess Sita made a Shivalinga using sand so that Rama could offer his prayers. It is believed that the self-same Shiva Linga, known as Ramalingam, is now worshipped at the Ramanathaswamy temple. The lingam brought by Hanuman from Kailash is called Vishwalingam.

There are 22 Theerthams (holy water bodies) inside the temple where devotees bathe to atone for their sins.