It is celebrated on the full moon day of Margashirsha (November-December) all over the country, and specially in Maharashtra. Dattatreya is the son of Rishi Atri and Anusuya. Anusuya, considered being a jewel in wifely devotion and virtue did severe penance to beget a son equal in merits to Brahma, Vishnu and Mahesha, the Hindu triad. The severity of her penance aroused the jealousy of Lakshmi, Saraswati and Parvati, and they sent their husbands Vishnu, Brahma and Shiva to test her virtue, by asking her to give them alms while nude.

They approached Anusuya in the guise of three mendicants and asked her to give alms with an uncovered body. She was on the horns of a dilemma for a while, but then she started reciting a mantra, sprinkled a little water over the three sanyasis at which they were instantly transformed into three babies, and her breasts at once swelled with milk. She took up the three babies and suckled them in a nude state. In the meantime Atri returned from his morning ablutions and was told about what had transpired during his absence. He already knew it through his divine vision. He fondly embraced the three children and they turned into one with three heads and six hands.

Lakshmi, Saraswati and Parvati got worried when their husbands did not return. They hurried to Anusuya and asked her to give back their husbands in alms. They also begged her forgiveness. Anusuya acceded to their request and the Trimurti of Vishnu, Brahma and Shiva appeared immediately in their real forms. They blessed the Rishi couple with the child Dattatreya.

Thus Dattatreya came to possess three heads and six hands. In him qualities of Brahma, Shiva, and more particularly of Vishnu, was incarnated. That is why he is worshiped as a Triad. He had three sons, Soma, Datta and Durvasa, to whom also a portion of the divine essence was transmitted. He was the patron deity of Karta-virya and gave him thousand arms. Dattatreya acquired knowledge from 24 objects which included the earth, water, fire, sky, moon, sun, pigeon, python, ocean, moth, honey-bee, elephant, deer, etc., and treated them as his preceptors and gurus.

On Dattatreya Jayanti people get up early in the morning and have ablutions in sacred streams, rivers, etc., observe fast and spend the day in meditation, prayer and worship. They meditate on the life of Dattatreya and read his works which include Avadhuta Gita and Jivanmukta Gita. The image of Dattatreya is worshipped with flowers, lamps, incense, camphor, etc., and the aspirants take resolve to follow the path of Swami Dattatreya.