Uma Maheshwara Vratam, also known as Uma Maheshvara Vrata, is dedicated to Shiva and Parvati and is observed on the 14th day or on the full moon day in the Bhadrapad month as per traditional Kannada calendar. In the Tamil Calendar, it is observed in the Puratassi month. In 2015, Uma Maheshvara Vratam as per Kannada calendar is on September 28.
A murti of Uma and Maheshwara (Shiva and Parvati) made of metal is worshipped on the day. The devotee observes a fast during the day and eats only after sunset on the day.
It is believed that the desires of the devotee will be fulfilled, if he observes the Uma Maheshwara Vratam.
Earlier, the Vrata was observed for 12 years on the full moon day in the Bhadrapad month. On the final year the metal murti of Uma and Maheshwara was donated to a Shiva temple.
Nowadays as per Tamil calendar, Uma Maheshwara Vratam is observed in Puratassi month. The Vrata can be observed on the Ashtami (eight day during waxing phase of moon), or Chaturdasi (14th day during waxing phase of moon) or Ammavasi (no moon day) or Pournima (full moon day).