| Class: | Listed |
| Horse Race: | Karndean Mares' Standard Open NH Flat Race |
| Location: | Cheltenham Racecourse Cheltenham, England |
| Race Type: | National Hunt flat race |
| Sponsor: | Karndean |
| Website: | Cheltenham |
| Distance: | 2 miles 87 yards (3,298 metres) |
| Surface: | Turf |
| Track: | Left-handed |
| Qualification: | Four to five years old fillies & mares |
| Weight: | 11 st 0 lb Penalties 4 lb for Class 1 winners |
| Purse: | £18,000 (2020) 1st: £10,251 |
|}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 3607yd), 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.
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| Year | Winner | Age | Jockey | Trainer | |
|---|---|---|---|---|---|
| 2013 | The Govaness | 4 | Paddy Brennan | Fergal O'Brien | |
| 2014 | Bitofapuzzle | 6 | Noel Fehily | Harry Fry | |
| 2015 | Copper Kay | 5 | Richard Johnson | Philip Hobbs | |
| 2016 (dh) | My Khaleesi Irish Roe | 5 5 | Wayne Hutchinson Graham Lee | Alan King Peter Atkinson | |
| 2017 | Posh Trish | 4 | Harry Cobden | Paul Nicholls | |
| 2018 | The Glancing Queen | 4 | Wayne Hutchinson | Alan King | |
| 2019 | Urban Artist | 4 | Nico de Boinville | Hughie Morrison | |
| 2020 (dh) | Elle Est Belle Ishkhara Lady | 4 6 | Harry Skelton Sean Bowen | Dan Skelton Harry Fry | |
| 2021 | Bonttay | 4 | Paddy Brennan | Fergal O'Brien | |
| 2022 | Queens Gamble | 4 | Jonathan Burke | Oliver Sherwood | |
| 2023 | Baby Kate | 4 | Brian Hayes | Willie Mullins | |
| 2024 | Seo Linn | 4 | Billy Lee | Paddy Twomey |