The David Nicholson Mares' Hurdle, currently known for sponsorship purposes as the Close Brothers Mares' Hurdle, is a Grade 1 National Hunt hurdle race in Great Britain which is open to mares aged four years or older.
It is run on the Old Course at Cheltenham over a distance of about 2 miles and 4 furlongs (2 miles, 3 furlongs and 200 yards, or 4,005 metres), and during its running there are ten hurdles to be jumped.
The race is scheduled to take place each year during the Cheltenham Festival in March.
Nicholson's record at the Cheltenham Festival included five victories as a jockey, and seventeen as a trainer.
This race was established in 2008, and in its inaugural year it was held on the final day of the Festival on Cheltenham's New Course.