जो अमावस्या सोमवार के दिन आती है, वह सोमवती अमावस्या कहलाती है. इस दिन चंद्रमा के दर्शन नहीं होते हैं. सोमवती अमावस्य पर भगवान शिव की पूजा अर्चना करके कमजोर चंद्रमा को बलवान किया जा सकता है. विवाहित स्त्रियां अपने पति की दीर्घायु के लिए सोमवती अमवस्या पर व्रत भी रखती हैं.
Amavasya is new moon day in Hindu calendar. It is significant day as many rituals are performed only on Amavasya Tithi. Amavasya falling on weekday Monday is known as Somvati Amavasya and Amavasya falling on weekday Saturday is known as Shani Amavasya. All Amavasya days are appropriate to perform Shraddha rituals to appease ancestors. Amavasya day is also appropriate day to perform Kalasarpa Dosha puja. Amavasya is also spelled and pronounced as Amavasai or Amavas.