The mystery woman dropped off an envelope containing cash at the Sue Ryder vintage shop in Headingley.
The charity, which was founded in Leeds in 1953, runs care homes for people with terminal illnesses and complex needs.
The donation will fund a hospice nurse for two months, a week's Hospice at Home care, 10 days of in-patient care and 100 bereavement counselling sessions.
A statement on the shop's Facebook page read:-
"We are so hugely grateful for this donation and the care it will help fund. Unfortunately we didn’t get a name from the lady who donated it, if you have any information please let us know so we can thank her in person!"
Sue Ryder was born in Leeds and served with the Special Operations Executive during World War Two, driving resistance agents to airfields.
She founded the charity after returning to England, and she lived at Scarcroft Grange. Ryder died in 2000.