The women's 100 metre backstroke event at the 2005 World Aquatics Championships took place between 25 July – 26 July. The heats and semifinals were held on 25 July. The final was held on 26 July.

Records

Prior to the competition, the existing world and championship records were as follows.

	Name	Nationality	Time	Location	Date
World record	Natalie Coughlin Natalie Coughlin Natalie Anne Coughlin is an American swimmer and eleven-time Olympic medallist.At the 2008 Summer Olympics, Coughlin became the first American female athlete in modern Olympic history to win six medals in one Olympics and the first woman ever to win a 100 m backstroke gold in two consecutive...	United States United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	59.58	Fort Lauderdale	13 August 2002
Championship record	Cihong He	China China Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...	1:00.16	Rome Rome Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...	10 September 1994

No new world or competition records were set during this competition.

Semifinals

Rank	Heat	Lane	Name	Nationality	Time	Notes
1	2	4	Natalie Coughlin Natalie Coughlin Natalie Anne Coughlin is an American swimmer and eleven-time Olympic medallist.At the 2008 Summer Olympics, Coughlin became the first American female athlete in modern Olympic history to win six medals in one Olympics and the first woman ever to win a 100 m backstroke gold in two consecutive...		1:00.59
2	2	5	Antje Buschschulte Antje Buschschulte Antje Buschschulte is a German swimmer. Her best disciplines are the short distance freestyle and backstroke races. Buschschulte swims for the sporting club SC Magdeburg. Up to now, she has won 24 German championships....		1:00.67
3	1	5	Hannah McLean Hannah McLean Hannah McLean is a New Zealand swimming competitor. She won a bronze medal in the 200m backstroke at the 2006 Commonwealth Games.She also competed at the 2004 Olympic Games.-References:...		1:01.14
4	1	4	Reiko Nakamura Reiko Nakamura is a Japanese Olympic and Asian record-holding swimmer. She swam in the 2004 and 2008 Olympic Games, winning the bronze medals in the 200m backstroke at both editions....		1:01.22
5	1	3	Hanae Ito Hanae Ito is a Japanese backstroke swimmer.-Major achievements:* 2005 World Championships – 100m backstroke 6th * 2006 Pan Pacific Swimming Championships – 100m backstroke 1st * 2008 Beijing Olympics – 100m backstroke 8th -Personal bests:...		1:01.25
6	2	6	Louise Ørnstedt Louise Ørnstedt Louise Ørnstedt was a Danish backstroke swimmer who competed at the 2000 and 2004 Olympics.She retired from swimming in August 2007 due to persistent shoulder problems.-References:*...		1:01.45
6	2	3	Kirsty Coventry Kirsty Coventry Kirsty Leigh Coventry is a Zimbabwean swimmer and world record holder. She attended and swam competitively for Auburn University in Alabama, in the United States...		1:01.45
8	2	7	Sophie Edington Sophie Edington Sophia Jane Edington is an Australian backstroke and freestyle swimmer.She trained at the Kingscliff ASC club under Greg Salter. After Greg took up an overseas coaching role Sophie moved to Queensland to train under the QAS program from the end of 2008...		1:01.64
9	1	1	Stanislava Komarova Stanislava Komarova Stanislava Stanislavovna Komarova is a Russian swimmer. She won the silver medal in the 200 m backstroke at the 2004 Summer Olympics in Athens.Komarova is one of the few modern swimmers who competes without goggles....		1:02.09
10	2	1	Alessia Filippi Alessia Filippi Alessia Filippi is an Italian swimmer.Filippi excels in backstroke and individual medley races, as well as in middle-distance freestyle ....		1:02.11
11	1	7	Yanyan Chen		1:02.34
12	1	6	Giaan Rooney Giaan Rooney Giaan Leigh Rooney OAM is a retired Australian swimmer. She won an Olympic gold medal and broke a world record at the Athens Olympics...		1:02.47
13	2	2	Janine Pietsch Janine Pietsch Janine Pietsch is a German backstroke swimmer. In the course of her career, she competed at the 2004 Summer Olympics in Athens, won two gold medals on the short course at the 2006 FINA World Swimming Championships, and four European gold medals.-2001–2005:Pietsch's first success on an...		1:02.49
14	1	8	Kateryna Zubkova Kateryna Zubkova Kateryna Mikhailivna Zubkova is a Ukrainian swimmer. She has won national titles for Ukraine eight times, and is a former European breaststroke champion...		1:02.60
15	1	1	Jeri Moss		1:02.68
16	2	8	Chang Gao		1:02.86

Final

Rank	Name	Nationality	Time	Notes
	Kirsty Coventry Kirsty Coventry Kirsty Leigh Coventry is a Zimbabwean swimmer and world record holder. She attended and swam competitively for Auburn University in Alabama, in the United States...		1:00.24
	Antje Buschschulte Antje Buschschulte Antje Buschschulte is a German swimmer. Her best disciplines are the short distance freestyle and backstroke races. Buschschulte swims for the sporting club SC Magdeburg. Up to now, she has won 24 German championships....		1:00.84
	Natalie Coughlin Natalie Coughlin Natalie Anne Coughlin is an American swimmer and eleven-time Olympic medallist.At the 2008 Summer Olympics, Coughlin became the first American female athlete in modern Olympic history to win six medals in one Olympics and the first woman ever to win a 100 m backstroke gold in two consecutive...		1:00.88
4	Reiko Nakamura Reiko Nakamura is a Japanese Olympic and Asian record-holding swimmer. She swam in the 2004 and 2008 Olympic Games, winning the bronze medals in the 200m backstroke at both editions....		1:01.00
5	Hannah McLean Hannah McLean Hannah McLean is a New Zealand swimming competitor. She won a bronze medal in the 200m backstroke at the 2006 Commonwealth Games.She also competed at the 2004 Olympic Games.-References:...		1:01.16
6	Hanae Ito Hanae Ito is a Japanese backstroke swimmer.-Major achievements:* 2005 World Championships – 100m backstroke 6th * 2006 Pan Pacific Swimming Championships – 100m backstroke 1st * 2008 Beijing Olympics – 100m backstroke 8th -Personal bests:...		1:01.25
7	Louise Ørnstedt Louise Ørnstedt Louise Ørnstedt was a Danish backstroke swimmer who competed at the 2000 and 2004 Olympics.She retired from swimming in August 2007 due to persistent shoulder problems.-References:*...		1:01.36
8	Sophie Edington Sophie Edington Sophia Jane Edington is an Australian backstroke and freestyle swimmer.She trained at the Kingscliff ASC club under Greg Salter. After Greg took up an overseas coaching role Sophie moved to Queensland to train under the QAS program from the end of 2008...		1:01.97