Ekaterina Andreevna Bychkova (Russian:Екатерина Андреевна Бычкова, born June 5, 1985) is a professional tennis player, born in Moscow, Russia. She is most famous for defeating defending champion Svetlana Kuznetsova in the first round of the 2005 U.S. Open. She defeated her by a score of 6–3, 6–2. It was the first time a defending U.S. Open Champion had lost in the first round. The win didn't last for long; Bychkova lost in the second round to Ivana Lisjak.
| Legend (Singles) |
| Grand Slam (0) |
| Tour Championships (0) |
| Tier I Event (0) |
| Tier II Event (0) |
| Tier III Event (0) |
| Tier IV Event (0) |
| ITF Circuit (6) |
| No. | Date | Tournament | Surface | Opponent in the final | Score |
| 1. | December 14 2003 | Cairo, Egypt | Clay | Gabriela Velasco Andreu | 6–1 6–4 |
| 2. | July 4 2004 | Krasnoarmeisk, Russia | Hard | Olga Panova | 6–2 6–3 |
| 3. | August 29 2004 | Moscow, Russia | Clay | Maria Kondratieva | 6–2 6–1 |
| 4. | March 27 2005 | St. Petersburg, Russia | Hard Indoors | Emma Laine | 6–1 6–2 |
| 5. | December 18 2005 | Bergamo, Italy | Carpet | Mervana Jugic-Salkic | 6–3 6–0 |
| 6. | June 19 2006 | Marseille, France | Clay | Severine Bremond | 6–1 6–2 |