Janmastami is one of the most auspicious Hindu festivals observed all over the country. It commemorates the birth of Krishna, the eighth incarnation of Vishnu, as the son of Vasudeva and Devaki.
The most important items in the worship of Krishna on his day of incarnation are fasting, worship, keeping awake in the night, and listening to chanting hymns of praise and legends relating to the pastimes of Krishna.
Krishna is invoked in an image. The ceremonies of the birth rites are performed symbolically. After offering prayer, night-long vigil is kept; the devotees listen to hymns glorifying Vishnu and Krishna. The next day, after the morning ablutions, the image of Krishna is worshiped and a feast is held.
- The Encyclopedia of Hinduism