Kim Clijsters and Ai Sugiyama were the defending champions, but Clijsters chose not to participate. Sugiyama played alongside Liezel Huber, but they lost in the first round to Shinobu Asagoe and Rika Fujiwara.
Alina Jidkova and Tatiana Perebiynis were the defending champions, but none entered this year. Perebiynis opted to rest in order to compete at Indian Wells the following week.
Shinobu Asagoe and Ai Sugiyama were the defending champions. They were both present but did not compete together.
Asagoe partnered with Tathiana Garbin, but lost in the semifinals to Conchita Martínez and Virginia Ruano Pascual.
Sugiyama partnered with Daniela Hantuchová, but lost in the semifinals to Anna-Lena Grönefeld and Martina Navratilova.
Virginia Ruano Pascual and Paola Suárez were the two-time defending champions, but were defeated in the final by Kim Clijsters and Ai Sugiyama 7–6(7–5), 2–6, 7–9.
Shinobu Asagoe and Els Callens were the defending champions but they competed with different partners that year, Asagoe with Nana Miyagi and Callens with Meilen Tu.
Kimiko Date and Ai Sugiyama were the defending champions but only Sugiyama competed that year with Shinobu Asagoe.
The 1999 Toyota Princess Cup singles was the tennis singles event of the third edition of the first hardcourt tournament after the US Open. Monica Seles was the two-time defending champion, but was defeated by Lindsay Davenport in the final to win the title.
Virginia Ruano Pascual and Paola Suárez were the defending champions and won in the final 6–2, 6–3, against Svetlana Kuznetsova and Martina Navratilova in straight sets. This was Ruano Pascual's 4th career Grand Slam doubles title and her 2nd title at the US Open. It was also Suárez' 4th career Grand Slam doubles title and her 2nd title at the US Open.
Lisa Raymond and Rennae Stubbs were the defending champions, but competed this year with different partners. Raymond teamed up with Lindsay Davenport and were eliminated in second round due to a withdrawal, while Stubbs teamed up with Elena Bovina and lost in first round.
Liezel Huber and Rachel McQuillan were the defending champions, but none of them competed this year. Huber played in the Kremlin Cup at the same week.
This was the first edition of the tournament.
Shinobu Asagoe and Katarina Srebotnik were the defending champions, but Srebotnik did not compete this year. Asagoe teamed up with María Vento-Kabchi and lost in the final 7–5, 4–6, 6–3 against Gisela Dulko and Maria Kirilenko.
Ai Sugiyama and Elena Tatarkova were the defending champions, but did not compete this year.
Jill Craybas was the defending champion, but lost in quarterfinals to Arantxa Parra Santonja.
Alicia Molik was the incumbent champion, but did not compete in 2004.
Teryn Ashley and Abigail Spears were the defending champions, but Spears decided to compete in Gold Coast at the same week. Ashley teamed up with Shenay Perry and lost in first round to Iveta Benešová and Renata Voráčová.
Cara Black and Elena Likhovtseva were the defending champions, but none competed this year. Black competed in Sydney at the same week, while Likhovtseva decided to focus only on the singles competition.
Maria Sharapova and Tamarine Tanasugarn were the defending champions, but none competed this year.
Maria Sharapova and Tamarine Tanasugarn were the defending champions, but decided to focus on the singles tournament only. Sharapova would eventually win the title.
Mervana Jugić-Salkić and Jelena Kostanić were the defending champions, neither chose to compete in 2005.
Maria Sharapova 
Tamarine Tanasugarn 
Ansley Cargill 
