The magazine's annual awards ceremony, which celebrates the year's most inspirational figures and their achievements, were hosted by Fearne Cotton from the Victoria and Albert Museum in London.
Osbourne was presented with the 'Ultimate VO5 Style Icon' award by BBC Radio 1 breakfast show host Nick Grimshaw and said that appearing on the cover of Cosmopolitan "did wonders" for her self-esteem.
Contostavlos was named 'Ultimate TV Personality', and dedicated the award to her friend and personal assistant Gareth Varey, who is recovering after fracturing his leg.
Scherzinger, meanwhile, was presented with the 'Ultimate Fun Fearless Female' award by her X Factor contestant Rylan Clark.
Ennis was recognised with the 'Ultimate Olympian' award for her gold medal-winning performance in the heptathlon at London 2012, while cyclist and triple London 2012 gold medallist Sarah Storey was named 'Ultimate Paralympian'.
Elsewhere, One Direction took home the award for 'Ultimate Men of the Year', while Olympic gymnast and Strictly Come Dancing contestant Louis Smith was named 'Ultimate Hottie'.
New X Factor USA host Khloe Kardashian shared the award for 'Ultimate Confidence Queens' with sisters Kim Kardashian and Kourtney Kardashian, and Fresh Meat actress Zawe Ashton was named 'Ultimate Newcomer'.
Further acting awards went to Vicky McClure ('Ultimate UK TV Actress') and Jennifer Lawrence ('Ultimate Film Actress').
The 'Editor's Choice' award was presented to Stephanie Kercher, whose sister Meredith Kercher was murdered five years ago in Perugia.
Digital Spy special reader offer: Print off this voucher for £1.50 off the November issue of Cosmopolitan featuring the magazine's 'Ultimate TV Personality' winner Tulisa Contostavlos on the cover and a free Missguided lip gloss in one of three kissable colours .
The full list of winners was as follows:
Ultimate Fun Fearless Female
Ultimate Style Icon with VO5
Ultimate Confidence Queens
Kourtney, Kim and Khloe Kardashian
Ultimate TV Personality
Ultimate Pop Star
Ultimate UK TV Actress
Ultimate International TV Actress
Ultimate Film Actress
Ultimate Family Girl
Ultimate Love Story
Emma and Chris Barton
Natasha Devon and Ruth Rogers
Ultimate Editor's Choice
Ultimate Street Style Icon with VO5
Cosmopolitan Ultimate Women of the Year Awards - photo gallery
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