Madonna's children's book The English Roses has sold just over 8,000 copies in its first week in the UK.
This was Madonna's first attempt at children's fiction
The book, launched amid a blaze of publicity, made it to number 17 in the national book chart, according to data company Nielsen Bookscan.
It was the second bestselling children's book of the week, behind JK Rowling's fifth Harry Potter book.
This week the top-selling book in the UK, David Beckham's autobiography My Side, sold 103,508 copies.
Madonna's book, her first for children, has been translated into 42 languages and is on sale in 100 countries.
The English Roses sold 8,270 copies in its opening week, 220 copies fewer than the number one children's book, JK Rowling's Harry Potter and the Order of the Phoenix, which was first published in June.
The Harry Potter book, which also backed by a massive marketing campaign, sold more than 1.7 million copies in the UK on it first day of release three months ago through bookshops and the internet.
Top 10 books in the UK
1 My Side: The Autobiography - David Beckham
2 Four Blind Mice - James Patterson
3 Kisscut - Karin Slaughter
4 The Lovely Bones - Alice Sebold
5 Red Rabbit - Tom Clancy
6 Life of Pi - Yann Martel
7 Portrait of a Killer: Jack the Ripper - Patricia Cornwall
8 Dr Atkins' New Diet Revolution - Robert Atkins
9 No 1 Ladies' Detective Agency - Alexander McCall Smith
10 Number Ten - Sue Townsend
Source: Nielsen Bookscan
To mark the launch of The English Roses, Madonna threw a tea party in Kensington, west London, on 14 September inviting friends and celebrities and their children , including actress Patsy Palmer and interior designer Linda Barker.
The guests were invited to walk up a pink, sparkly carpet, surrounded by barriers adorned with butterflies and roses.
Madonna then read an extract of the book, aimed at children over the age of six, to the assembled young audience.
Children's poet Michael Rosen commented that in the book "Madonna takes on the voice of a slightly bossy teacher, telling her readers to not interrupt and to listen carefully" in a review of The English Roses for BBC News Online.