Margashirsha Purnima is the full moon day in Margashirsha Month as per Hindu calendar. In 2016, Margashirsha Purnima date is December 13.
Margashira Pournami marks the end of Margashirsha Month in North Indian Hindi calendars and marks the ending of Shukla Paksha in Margashirsha Month in Marathi, Gujarati, Telugu & Kannada calendars.
Full Moon in Margashirsha Month is also observed as Dattatreya Jayanti. It celebrates the first appearance day of Lord Dattatreya Swamy, who is an incarnation of Trimurthi (Shiva, Vishnu and Brahma).
It is also celebrated as Annapurna Jayanti Puja. Annapurna Mata is considered as the Goddess of food and nutrition.