Julien Boutter was the defending champion, but lost in the second round this year.

Santiago Ventura won the title, defeating Dominik Hrbatý 6–3, 1–6, 6–4 in the final. Notably, this was Ventura's first ATP Tour-level appearance.

	Semifinals							Final
	1	Dominik Hrbatý	6	6
		Julien Benneteau	2	2
								1	Dominik Hrbatý	3	6	4
								Q	Santiago Ventura	6	1	6
		Christophe Rochus	1	6	2
	Q	Santiago Ventura	6	1	6

	First round							Second round							Quarter-finals							Semi-finals
	1	D Hrbatý	6	6
		P Kohlschreiber	2	2				1	D Hrbatý	5	6	6
		G Elseneer	3	6	4				Á Calatrava	7	4	4
		Á Calatrava	6	4	6										1	D Hrbatý	6	6
		J-P Guzmán	6	6											8	Ó Hernández	3	0
		E Taino	2	1					J-P Guzmán	4	6	63
	WC	M El Aarej	4	4				8	Ó Hernández	6	1	77
	8	Ó Hernández	6	6																		1	D Hrbatý	6	6
	4	R Ramírez Hidalgo	4	2																			J Benneteau	2	2
		J Benneteau	6	6					J Benneteau	2	6	6
		J Boutter	6	3	6				J Boutter	6	3	4
	WC	M Ziadi	1	6	1											J Benneteau	6	6
	Q	Z Krajan	3	5											7	T Ascione	3	4
		F Browne	6	7					F Browne	2	1r
	WC	M Tahiri	3	4				7	T Ascione	6	3
	7	T Ascione	6	6

	First round							Second round							Quarter-finals							Semi-finals
	5	C Saulnier	6	6
		S Pescosolido	3	2				5	C Saulnier	0	3
		F Vicente	5	1					C Rochus	6	6
		C Rochus	7	6												C Rochus	6	6
		A Portas	6	7											3	A Dupuis	3	1
		O Mutis	2	5					A Portas	64	62
	Q	A di Pasquale	67	4				3	A Dupuis	77	77
	3	A Dupuis	79	6																			C Rochus	1	6	2
	6	D van Scheppingen	4	2																		Q	S Ventura	6	1	6
		I Heuberger	6	6					I Heuberger	6	6
	Q	S Vagnozzi	79	6				Q	S Vagnozzi	3	4
		J-R Lisnard	67	1												I Heuberger	2	4
	Q	S Ventura	6	6											Q	S Ventura	6	6
		R Sabău	2	3				Q	S Ventura	77	6
		N Mahut	6	6					N Mahut	65	4
	LL	B Rehnquist	1	2

• Association of Tennis Professionals (ATP) – 2004 Grand Prix Hassan II Men's Singles draw