The most important festival during the Mandalam period, lasting for a month. It was on the Guruvayur Ekadasi day that Lord Krishna revealed the Gita to Arjuna. An udayastamana Pooja is conducted by the Devaswam. A memorial service for GajarajanKesavan is also held on that day. The head of the elephant family places a wreath in front of the statue of their departed leader while all the other pachyderms stand around and pay homage

Chembai Music Festival:
This karnatic music festival is held for 11 days in the memory of Sri Chembai Vaidyanadha Bhagavathar, a great Karnatic musician and a devotee of Guruvayurappan, as part of the Ekadasi celebrations. Nearly 4000 artistes participate- young and old, amateurs and professionals, vocalists and instrumentalists. They are provided with free food, accommodation and prasadam by the Guruvayur Devaswom.

Chembai Vaidyanatha Bhagavatar was an Indian Carnatic music singer from the state of Kerala. Usually known by his village name Chembai, or simply as Bhagavatar, he was born to Anantha Bhagavatar and Parvati Ammal in 1895.[1] Chembai was noted for his powerful voice and majestic style[2] of singing. His first public performance was in 1904, when he was nine. He was a recipient of several titles and honours in his performing career of 70 years (1904-1974).[3] He was known for his encouragement of upcoming musicians, and also for his ability to spot new talent.[1] He was responsible for popularizing compositions like Rakshamam, Pavana Guru, among others.[4] The music critic 'Aeolus' describes him as "the musician who has meant the most to Carnatic Music in the first fifty years of the 20th century"[5] Some of his prominent disciples include Yesudas, T.V.Gopalakrishnan, V.V.Subramaniam, P.Leela, among others.[6] Many memorial music festivals are held in his honour annually since his death in 1974, the most important being the annually celebrated Chembai Sangeetholsavam.