
Rendell suffered a stroke in January and had been in a critical condition in hospital.
In a statement, Penguin Random House said: "We are devastated by the loss of one of our best-loved authors."
"We will miss her enormously," it said.

Ruth Rendell was one of Britain's best-selling authors who published more than 60 books in a career spanning five decades. PHOTO AFP
Gail Rebuck, chair of Penguin Random House UK, said: "Ruth was much admired by the whole publishing industry for her brilliant body of work.
"An insightful and elegant observer of society, many of her award-winning thrillers and psychological murder mysteries highlighted the causes she cared so deeply about," she said.
Rendell was best known for psychological thrillers delving into the criminal mind as well as the successful television adaptation "The Ruth Rendell Mysteries".
Her fictional creation, the sensitive Chief Inspector Reginald Wexford, featured in her first novel "From Doon to Death" (1964) and throughout her career.
Following were some of the reactions on Twitter on the demise of the author:
"Some say life is the thing, but I prefer reading." Sad to say goodbye to Ruth Rendell this morning. One of the best. pic.twitter.com/xw6g1hr64J
— Vintage Books (@IReadVintage) May 2, 2015
We are deeply saddened by the loss of one of our best-loved authors, Ruth Rendell. http://t.co/Q9TGXaYveu
— Penguin Books UK (@PenguinUKBooks) May 2, 2015
Sad to hear of the death of Ruth Rendell. A favourite with booksellers and our customers. BBC News - Author Ruth Rendell dies aged 85
— Waterstones Piccadilly, London (@WaterstonesPicc) May 2, 2015
So sorry to hear that Ruth Rendell has died. A prolific writer, but also a Labour peer, a dedicated, engaging & witty colleague. RIP
— Maeve Sherlock (@MaeveSherlock) May 2, 2015
"I think about death every day - what it would be like. It would be humiliating to be afraid"
— Andrew Wilson (@ACWils) May 2, 2015
Ruth #Rendell RIP pic.twitter.com/6r3JYqdo9Z
RIP Ruth Rendell: great inspiration, great woman, great radical, and she was lovely when she met our children.
— Nicci French (@FrenchNicci) May 2, 2015
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