Officials at Chepstow Racecourse have decided to abandon the Welsh National, which was due to be run on Thursday.
Clerk of the course Keith Ottesen called an inspection earlier today and decided that the waterlogged surface would have posed a major danger to the horses.
"We needed some periods of dry weather between the rain. It didn't rain yesterday, but we still wouldn't have been fit to race," said Ottesen.
"The Welsh National is one of the most testing races of the year and we have to make sure it is fair and safe to the horses, which it wouldn't have been."
The race has since been rescheduled for Saturday, January 5.
