Vaikuntha Ekadashi is a major observance of the Vaishnava traditions of the south, kept on the ekadashi (eleventh day) of the bright fortnight of the month of Margashirsha/Dhanurmasa (December-January). Ekadashi days, twice a lunar month, are set aside across Hinduism for fasting and the worship of Vishnu, but this one is held to be the most powerful of the year: tradition teaches that on this day the gate of Vaikuntha, the heaven of Vishnu, stands open, and that those who fast, keep vigil and pass through the temple's northern "gate of Vaikuntha" (Vaikuntha Dvara) are granted liberation or a place in the Lord's abode.
The observance is centered on the great southern Vishnu temples, above all Srirangam, where enormous crowds pass through the ceremonially opened northern gateway, and Tirupati. Devotees keep a strict fast, often waterless, and spend the day and night in prayer, recitation and the singing of the Tiruppavai and other Tamil devotional hymns. The day belongs to the wider practice of ekadashi fasting, understood both as bodily discipline and as an intensification of devotion, but its promise of the open gate of heaven gives Vaikuntha Ekadashi a special place, drawing even the occasional devotee to keep at least this one fast in the year.