Durvashtami Puja or Doorvashtami Vrata is observed on the eighth day of Shukla Paksha during Bhadrapad month. In 2016, Durvashtami Puja date is 9.
Durvashtami festival is dedicated to Goddess Gauri and Lord Ganesh. On Durvastami day, devotees worship Lord Ganesh and Gauri with Durva grass blades (Garika or Darbha).
The performers of Durvastami vrata, observe fasting during the day. Devotees also worship Lord Shiva with Bilva Patra (Bell leaves). Fruits and flowers are offered to Shiva during the vratha.
Performing the Durvashtami Vratha makes one free from all the sins that he/she is committed in whole life. Durvashtami is also celebrated as Radhashtami or Radha Ashtami by Vaishnava sects especially in Vrindavan, Puri, Mathura and ISKCON Temples all around the world.