In the epic Mahabharata, Ambika is the daughter of Kashya, the King of Kashi, and wife of Vichitravirya, the king of Hastinapura.
Along with her sisters Amba and Ambalika, she was taken by force by Bhishma from their Swayamvara. Bhishma challenged the assembled Kings and Princes and defeated them. He presented them to Satyavati for marriage to Vichitravirya. Vichitravirya married only Ambika and Ambalika, and refused to marry Amba since she had already given her heart to another.
After Vichitravirya's death, his mother Satyavati sent for her first born, Rishi Veda Vyasa. According to his mother's wishes, he visited both the wives of Vichitravirya to grant them each a son under the Niyoga system. When Vyasa visited Ambika, she saw his dreadful, forbidding appearance and burning eyes. In her frightened state, she closed her eyes. Hence her son, Dhritarashtra, the father of the Kauravas, was born blind.
In a few versions of the Mahabharatha, Ambika is shown to have no strong motherly feelings towards her blind son Dhritarashtra, as he was a son unwanted to her.
After Dhritarashtra's birth, when Satyavati requested Vyasa to visit Ambika for the second time, she dared not go and sent her maid instead. The maid also bore a son, Vidura, who was raised as a brother of Dhritarashtra and Pandu. Much later, Ambika accompanied Satyavati and Ambalika to the forest and ended her life in austerities.