The two sisters — 29-year-old Kate and 28-year-old Pippa — came first and second, and beat many celebrities including Beyonce, Victoria Beckham and Cheryl Cole in a poll of 3,000 women.
Cheryl Cole came third with pop star Rihanna making the fourth spot in the survey conducted by Superdrug, reported the Daily Express.
Television presenter Holly Willoughby came fifth, while Tulisa Contostavlos and Beyonce came sixth and seventh respectively.
Harry Potter actress Emma Watson was eighth, followed by singer Katy Perry and Victoria Beckham in 10th place.
“Our Beauty Icons survey gives a snapshot of the changing face of British beauty. A key change is the continued rise of the brunette, with three-quarters of the top 20 sporting brown hair,” said Superdrug beauty director Sara Wolverson.