Rafael Nadal defeated Ivan LjubiÃÂiÃÂ in the final, 3–6, 2–6, 6–3, 6–4, 7–6<sup>(7–3)</sup> to win the singles tennis title at the 2005 Madrid Open. Throughout his entire career, this remained his sole indoor hardcourt title.
Marat Safin was the reigning champion, but chose not to compete.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated. All sixteen seeds received a bye into the second round.