Yagnavalkya was son of Brahmrath (also known as Vajasani and Devrath) and Sunanda.

Brahmrath had good knowledge of Ved's and Sastra's. He was also known as Vajasani as he used to do anndan (donate food) daily and he was also known as Devrath because almighty himself blessed him with a son.

Sunanda was the daughter of the Rishi Sakala she gave birth to Yagnavalkya on the twelfth day of bright fortnight, i.e. Shukla Paksh in the month of Kartik, Sud Dwadasi Thithi, Sathaya Nakshatra, Danur Lagna, a most auspicious and pious day and time. Indian Panchang refers this day as Yogeeswar Dwadasi.

After the birth of Yagnavalkya, Brahmrath and Sunanda also had a daughter known as Kamsari. Yagnavalkya was master in performing Yagnas and it was because of his this mastery in performing Yagnas as easily as changing of dress that he was called Yagnavalkya which means a man who puts yagna as a dress.

Yajnavalkya had two wives. One was Maitreyi and the other Katyayani. Maitreyi was a Brahmavadini. When Yajnavalkya wished to divide his property between the two wives before starting his Sanyas Ashram his wife Maitreyi asked whether she could become immortal through wealth.

Yajnavalkya replied that is not possible and so Maitreyi requested Yajnavalkya to teach her what he considered as the best after that Yajnavalkya gave her the true and infinite knowledge. This immortal conversation between Yajnavalkya and Maitreyi is recorded in the Brihadaranyaka Upanishad.

Yajnavalkyas other wife Katyayani, the daughter of Bharadhwaj, was of common intelligence and through her Yajnavalkya had three sons Chandrakanta, Mahamegha and Vijaya.

Once King Janak wanted to learn Brahm Vidya and for that he conducted debate to find out who was possessed highest knowledge for this he offered one thousand cows with their calves, all their horns being decked with enormous gold. No person dared to enter this debate but Yajnavalkya stood up. He was asked many questions for which he promptly replied and won the debate.

The third and the fourth chapters of the Brihadaranyaka Upanishad consist of philosophical teachings of Yajnavalkya. Yajnavalkya was also the author of the famous Yajnavalkya Smriti, Yajnavalkya Shakha, Pratijna Sutra, Shatpath Brahman, and Yog Yajnavalkya.

At the end of his days Yajnavalkya took Sanyas and went to the forest.