Buddha Poornima or Buddha Purnima or Buddha Jayanti is the most sacred day in the Buddhist calendar. The most important festival of the Buddhists, Buddha Purnima falls on the full moon day of the lunar month Vaishaaka (that corresponds to the month of April-May) - a special time in Buddhism as it was on this day that the Buddha was born, gained enlightenment and attained Nirvana when he died. To mark the occasion, It is also believed that Yashodara, Gautam's wife, his charioteer Channa and even his horse Kantaka were born on the same day.

Gautam Buddha was born as a prince in 544 BC in Lumbini, Nepal on a Full Moon day in the month of Vaisakh. When he was born it was predicted that the child would redeem the world. Even as a young prince he was touched by the pain and sickness of others. Later he renounced the world and became an ascetic. At the age of 35, he attained enlightenment on the full moon day of Vaisakh. He traveled far and wide preaching the truth and gained a large following consisting of scholars, sanyasis, rulers of states and others, thus forming the Buddhist community.

In this day the followers of Buddha bathe and wear only white clothes. They gather in their Viharas for worship and give alms to monks. Prayers, sermons, and non-stop recitation of Buddhist scriptures resonate in monasteries and viharas. The statue of the Buddha receives special attention everywhere, with people offering it incense, flowers, candles, and fruits. Since Buddha attained enlightenment sitting under a Bodhi (Pipal) tree, special care is taken in watering and tending Bodhi trees. They light lamps around the trees and decorate with garlands and coloured flags. They reaffirm their faith in the five principles called 'Panch Sheel'. The five principles are not to take life, not to steal, not to lie, not to imbibe liquor or other intoxicants and not to commit adultery. On this day, the Buddhists free birds from cages, distribute fruit and clothes to the sick and refrain from eating meat.

Bodh Gaya in Bihar and Sarnath in Uttar Pradesh are the main centers of celebration of this festival. Besides these two, areas with large Buddhist population like Ladakh, Sikkim, and Arunachal Pradesh also celebrate this festival with great devotion and enthusiasm.