Belarussia's Victoria Azarenka, who beat Williams in Sunday's final of the Cincinnati Open, is the second seed ahead of Maria Sharapova of Russia and Poland's Agnieszka Radwanska.
Williams heads into the Open, which starts on August 26, looking to add to her French Open title from this year, her 16th Grand Slam singles triumph, which includes four championships at Flushing Meadows.
Williams' sister Venus, a two-times US Open winner but currently ranked 60th in the world, was unseeded.
Serbia's Novak Djokovic is the top seed in the men's draw which includes five-times US Open champion and 17-times Grand Slam winner Roger Federer as seventh seed - his first time the Swiss has been placed outside the top three in a Grand Slam in over ten years.
Spaniard Rafa Nadal is the number two seed, ahead of Britain's Andy Murray, the defending champion and this year's Wimbledon winner.
The draw for the tournament will be held on Thursday.
| Seedings for men's singles: | Seedings for women's singles: |
| 1. Novak Djokovic, Serbia | 1. Serena Williams, United States |
| 2. Rafael Nadal, Spain | 2. Victoria Azarenka, Belarus |
| 3. Andy Murray, Great Britain | 3. Maria Sharapova, Russia |
| 4. David Ferrer, Spain | 4. Agnieszka Radwanska, Poland |
| 5. Tomas Berdych, Czech Republic | 5. Sara Errani, Italy |
| 6. Juan Martin Del Potro, Argentina | 6. Li Na, China |
| 7. Roger Federer, Switzerland | 7. Caroline Wozniacki, Denmark |
| 8. Richard Gasquet, France | 8. Petra Kvitova, Czech Republic |
| 9. Stanislas Wawrinka, Switzerland | 9. Angelique Kerber, Germany |
| 10. Milos Raonic, Canada | 10. Jelena Jankovic, Serbia |
| 11. Kei Nishikori, Japan | 11. Roberta Vinci, Italy |
| 12. Tommy Haas, Germany | 12. Samantha Stosur, Australia |
| 13. John Isner, United States | 13. Kirsten Flipkens, Belgium |
| 14. Jerzy Janowicz, Poland | 14. Ana Ivanovic, Serbia |
| 15. Nicolas Almagro, Spain | 15. Maria Kirilenko, Russia |
| 16. Fabio Fognini, Italy | 16. Sloane Stephens, United States |
| 17. Kevin Anderson, South Africa | 17. Sabine Lisicki, Germany |
| 18. Janko Tipsarevic, Serbia | 18. Dominika Cibulkova, Slovakia |
| 19. Tommy Robredo, Spain | 19. Carla Suarez Navarro, Spain |
| 20. Andreas Seppi, Italy | 20. Sorana Cirstea, Romania |
| 21. Mikhail Youzhny, Russia | 21. Nadia Petrova, Russia |
| 22. Philipp Kohlschreiber, Germany | 22. Simona Halep, Romania |
| 23. Feliciano Lopez, Spain | 23. Elena Vesnina, Russia |
| 24. Benoit Paire, France | 24. Jamie Hampton, United States |
| 25. Grigor Dimitrov, Bulgaria | 25. Ekaterina Makarova, Russia |
| 26. Sam Querrey, United States | 26. Kaia Kanepi, Estonia |
| 27. Fernando Verdasco, Spain | 27. Alize Cornet, France |
| 28. Juan Monaco, Argentina | 28. Svetlana Kuznetsova, Russia |
| 29. Jurgen Melzer, Austria | 29. Mona Barthel, Germany |
| 30. Ernests Gulbis, Latvia | 30. Magdalena Rybarikova, Slovakia |
| 31. Julien Benneteau, France | 31. Laura Robson, Great Britain |
| 32. Dmitry Tursunov, Russia | 32. Klara Zakopalova, Czech Republic |
Image: Roger Federer
Photograph: Thomas Lovelock/AELTC - Pool/Getty Images
Williams to face Azarenka for Cincinnati crown
Williams storms into last four in Cincinnati
Azarenka crushes Serena Williams to win Cincinnati title
PHOTOS: Tendulkar cheers for Mumbai Masters in IBL
Radwanska withdraws from Cincinnati