The 2005 J&S Cup was a Tier II event on the 2005 WTA Tour that run from 25 April 25 until 1 May 2005. It was held on outdoor clay courts in Warsaw, Poland, and was the 10th year that the event was staged. Unseeded Justine Henin-Hardenne won her first Warsaw title and second overall of the year.

Finals

Singles

🇧🇪 Justine Henin-Hardenne defeated 🇷🇺 Svetlana Kuznetsova, 3–6, 6–2, 7–5

Doubles

🇺🇦 Tatiana Perebiynis / 🇨🇿 Barbora Strýcová defeated 🇵🇱 Klaudia Jans / 🇵🇱 Alicja Rosolska, 6–1, 6–4

Entrants

Seeds

Other entrants

The following players received wildcards into the main draw: The following players received entry from the qualifying draw: The following players received entry as lolly losers: