Naga Chaturthi upvaas vrat is observed a day prior to Nag Panchami festival. It is dedicated to Naga Devtas (Serpent Gods & Goddesses). In 2012, Naga Chaturthi Upvaas date is July 22, Sunday.
It is widely observed in all over India mainly in North India, Karnataka, and Andhra Pradesh. Nag Chaturthi is observed on Shukla Paksha Chaturthi in Shravan month as per all Hindu lunar calendars of India.
Women observe fasting on Nag Chaturthi day. They perform special pujas to the Snake Gods on Nag Panchami.