Marat Safin defeated David Nalbandian in the final, 6–2, 6–4, 6–3 to win the singles tennis title at the 2004 Madrid Open.^[1]

Juan Carlos Ferrero was the defending champion, but lost to Luis Horna in the second round.

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.

	Quarterfinals							Semifinals							Final
		Ivan Ljubičić	77	61	77
	7	Joachim Johansson	62	77	63
									Ivan Ljubičić	4	4
								4	David Nalbandian	6	6
	4	David Nalbandian	77	6
		Taylor Dent	64	3
															4	David Nalbandian	2	4	3
															3	Marat Safin	6	6	6
		Luis Horna	4	4
	3	Marat Safin	6	6
								3	Marat Safin	6	77
								2	Andre Agassi	3	64
	8	Tommy Robredo	77	3	2
	2	Andre Agassi	63	6	6

	First round							Second round							Third round							Quarterfinals
								1	T Henman	6	6
		I Labadze	2	7	5				A Costa	4	2
		A Costa	6	5	7										1	T Henman	4	6	2
	Q	T Berdych	4	4												I Ljubičić	6	4	6
		I Ljubičić	6	6					I Ljubičić	6	6
								13	R Schüttler	3	0
																							I Ljubičić	77	61	77
																						7	J Johansson	62	77	63
								12	J I Chela	64	3
	Q	A Dupuis	6	6				Q	A Dupuis	77	6
		A Calleri	4	4											Q	A Dupuis	1	66
	Q	K Vliegen	7	5	1										7	J Johansson	6	78
		G Cañas	5	7	6				G Cañas	63	5
								7	J Johansson	77	7

	First round							Second round							Third round							Quarterfinals
								4	D Nalbandian	77	6
		R Söderling	6	77					R Söderling	65	3
		F Mayer	3	62											4	D Nalbandian	6	6
	WC	À Corretja	7	6											16	P Srichaphan	3	1
	WC	D Ferrer	5	1				WC	À Corretja	65	3
								16	P Srichaphan	77	6
																						4	D Nalbandian	77	6
																							T Dent	64	3
								11	J Novák	1	4
		T Haas	6	6					T Haas	6	6
		X Malisse	4	1												T Haas	63	2
		T Dent	6	6												T Dent	77	6
		M Youzhny	3	2					T Dent	6	3	6
								5	N Massú	3	6	3

	First round							Second round							Third round							Quarterfinals
								6	J C Ferrero	3	1
		L Horna	6	7					L Horna	6	6
		H Arazi	4	5												L Horna	7	6
		M Ančić	6	4	4										9	A Pavel	5	4
		M Fish	0	6	6				M Fish	1	6	62
								9	A Pavel	6	3	77
																							L Horna	4	4
																						3	M Safin	6	6
								15	F González	1	6	65
	Q	S Koubek	6	6				Q	S Koubek	6	3	77
		S Schalken	4	4											Q	S Koubek	3	3
		I Karlović	4	712	65										3	M Safin	6	6
		F López	6	610	77				F López	5	77	3
								3	M Safin	7	65	6

	First round							Second round							Third round							Quarterfinals
								8	T Robredo	6	3	6
	Q	J L T Rascon	1	4					R Ginepri	4	6	3
		R Ginepri	6	6											8	T Robredo	2	6	6
		J Björkman	1	2												F Verdasco	6	4	3
		F Verdasco	6	6					F Verdasco	6	77
								10	D Hrbatý	4	64
																						8	T Robredo	77	3	2
																						2	A Agassi	63	6	6
								14	V Spadea	6	4	6
		R Nadal	6	6					R Nadal	4	6	3
	SE	D Sanguinetti	2	1											14	V Spadea	1	3
	WC	D Sánchez	3	63											2	A Agassi	6	6
	Q	M Mirnyi	6	77				Q	M Mirnyi	65	3
								2	A Agassi	77	6

1. Davide Sanguinetti (reached the semifinals at Vienna)

	First round							Qualifying competition
	1	Tomáš Berdych	4	6	6
		Jarkko Nieminen	6	3	3
								1	Tomáš Berdych	7	77
								9	Olivier Rochus	5	65
	WC	Andreas Seppi	3	5
	9	Olivier Rochus	6	7

	First round							Qualifying competition
	2	Filippo Volandri	6	6
	WC	Quino Muñoz	3	1
								2	Filippo Volandri	77	3	4
								WC	Tati Rascón	64	6	6
	WC	Tati Rascón	6	63	6
	8	José Acasuso	3	77	3

	First round							Qualifying competition
	3	Thomas Johansson	66	6	6
	Alt	Nicolás Almagro	78	1	3
								3	Thomas Johansson	4	4
									Stefan Koubek	6	6
		Stefan Koubek	1	6	6
	12	Jan-Michael Gambill	6	4	1

	First round							Qualifying competition
	4	Mariano Zabaleta	3	77	4
		Kristof Vliegen	6	62	6
									Kristof Vliegen	6	6
								7	Alberto Martín	2	4
		Álex Calatrava	6	4	3
	7	Alberto Martín	2	6	6

	First round							Qualifying competition
	5	Thomas Enqvist	6	2	6
		Potito Starace	3	6	4
								5	Thomas Enqvist	5	62
								11	Max Mirnyi	7	77
		Grégory Carraz	3	1
	11	Max Mirnyi	6	6

	First round							Qualifying competition
	6	Ricardo Mello	77	2	2
	Alt	Antony Dupuis	63	6	6
								Alt	Antony Dupuis	6	6
								WC	Guillermo García López	4	4
	WC	Guillermo García López	5	6	77
	10	Gilles Müller	7	3	64

• 2004 Main draw
• 2004 Qualifying draw
• ATP tournament profile