Prathamastami is a ritual/festival held in Odisha praying for the life and prosperity of the eldest child of a family.

The first child after completion of its one year is made to wear new clothes and offered a lighted lamp ovation by the senior female relatives followed by elaborate rituals during which the Mantras are recited.

The celebration falls on the eighth day of moon waning phase—Ashtami—of the month of Margashira according to the Odia calendar, occurring on the eighth day after Kartik Purnima.

The ritual involves Arti of the eldest child by mother and relatives in which the maternal uncle sends the items necessary for the rituals like new clothes, coconut, jaggery, newly harvested rice, black gram, turmeric leaves, coconut and other things(etc).

Ganesha, Shashti devi and the family deity are worshipped.