The Karndean Mares' Standard Open NH Flat Race is a Listed National Hunt flat race in Great Britain which is open to fillies and mares aged four or five years.
It is run on the Old Course at Cheltenham over a distance of about 2 miles and ½ furlong (2 miles and 87 yards, or 3,298 m), and it is scheduled to take place each year in November.
[1] The race has been run under various names since its inception.
Prior to 2023 the race was also open to six-year-olds.