On the day of Gai Jatra, families who have lost the member during the past year parade a decorated cow around the city. Others dress up kids as cows or ascetics and walk in procession. The animal is believed to help departed souls in their journey into the after-world. In Kathmandu, the bereaved families process proceed along the festival route individually. In Patan, the participants gather at Dubar Square and then move out together.

This festival was started to be celebrated from the period of Pratap Malla's rule who is the builder of Rani Pokhari in Kathmandu. He organized this festival to make his Queen happy, who had lost her beloved younger son. The King wanted to show the Queen that she is not only the one who had lost her beloved son but there are many others like her.