Mammiyur Mahadeva Temple is a popular Shiva temple situated in Guruvayoor, Thrissur district of Kerala, India. Every devotee who goes to Guruvayur Temple is supposed to go to Mammiyoor also, as the ritual goes. Only Hindus are allowed inside the temple premises. The temple is a part of the 108 famous Shiva temples in Kerala and one among the five Shiva temples around Guruvayoor. The main deity is Lord Shiva, who is installed in the concept of 'Uma Maheshwara' - His form with Goddess Parvathi on his left. There is a shrine for Lord Vishnu also here. The sub-deities are Lord Ganapathi, Lord Subrahmanya, Lord Ayyappan, Goddess Bhadrakali, Brahmarakshasa and Serpent deities. This temple is managed by Malabar Devaswom Board. Daily three poojas are conducted. Puzhakkara Chennas Mana is the hereditary Thanthri of this temple too. Shivaratri and Ashtami Rohini are the major festivals.
It is believed that Brihaspati and Vayu reached the banks of rudratheertha where Lord Shiva was doing a great penance searching a place to install the idol of Lord Vishnu which was worshiped by Lord Krishna himself. By understanding the importance of the idol, he suggested that the idol be consecrated in the banks of rudratheertha and moved to the opposite side of the lake to give space for the new shrine. Because of Lord Shiva 's sacrifice the place became to known as 'Mahimayur' which means place of glory by time it came to be known as 'Mammiyoor'