Henrietta Knight has announced her retirement, the three-times Gold Cup-winning trainer said on her website.
Knight, 65, will give up her National Hunt licence to spend more time with her husband, Terry Biddlecombe, who suffered a stroke last October.
The handler will forever by synonymous with Best Mate, who won three consecutive Gold Cups at the Cheltenham Festival between 2002-04.
Knight said on www.henandterry.com: "After much deliberation, and largely due to my husband Terry Biddlecombe's continued ill health, I have decided to hand in my trainer's licence.
"I have been incredibly lucky to have experienced some wonderful moments since I first began training in 1989."