Amélie Mauresmo won the singles tennis title at the 2004 WTA German Open by walkover, as her opponent Venus Williams withdrew due to a left ankle strain. It was the first title of the year for Mauresmo, and the 11th title of her career.

Justine Henin-Hardenne was the two-time reigning champion, but did not compete this year due to a cytomegalovirus.

The first eight seeds received a bye into the second round.

	Quarterfinals							Semifinals							Final
		Karolina Šprem	6	6
		Fabiola Zuluaga	3	3
									Karolina Šprem	6	3	4
								PR/3	Venus Williams	2	6	6
	PR/3	Venus Williams	77	5	6
	11	Paola Suárez	65	7	2
															PR/3	Venus Williams
															2	Amélie Mauresmo	w/o
	6	Jennifer Capriati	6	6
	4	Anastasia Myskina	3	2
								6	Jennifer Capriati	2	0
								2	Amélie Mauresmo	6	6
	10	Svetlana Kuznetsova	77	3	1
	2	Amélie Mauresmo	65	6	6

	First round							Second round							Third round							Quarterfinals
								1	K Clijsters	6	2	6
	Q	ME Camerin	2	3				Q	M Marrero	3	6	4
	Q	M Marrero	6	6											1	K Clijsters
	WC	A-L Grönefeld	4	2												K Šprem	w/o
		K Šprem	6	6					K Šprem	6	77
		M Shaughnessy	6	6					M Shaughnessy	2	63
	15	J Dokic	0	3																			K Šprem	6	6
	9	V Zvonareva	6	6																			F Zuluaga	3	3
	Q	T Perebiynis	3	4				9	V Zvonareva	1	77	1
		F Zuluaga	7	6					F Zuluaga	6	62	6
	PR	S Testud	5	1												F Zuluaga	77	3	6
		M Pierce	77	5	63										8	A Sugiyama	64	6	4
		E Likhovtseva	63	7	77				E Likhovtseva	1	2
								8	A Sugiyama	6	6

	First round							Second round							Third round							Quarterfinals
								PR/3	V Williams	7	6
	Q	T Golovin	5	6	3				E Daniilidou	5	3
		E Daniilidou	7	3	6										PR/3	V Williams	6	6
		N Dechy	6	77											16	A Smashnova-Pistolesi	3	1
	Q	B Strýcová	4	64					N Dechy	6	4	1
		M Maleeva	3	1				16	A Smashnova-Pistolesi	1	6	6
	16	A Smashnova-Pistolesi	6	6																		PR/3	V Williams	77	5	6
	11	P Suárez	6	7																		11	P Suárez	65	7	2
	Q	A Medina Garrigues	2	5				11	P Suárez	6	6
		B Schett	6	6					B Schett	4	3
	LL	K Srebotnik	3	3											11	P Suárez	6	78
		A Barna	4	79	6										5	N Petrova	1	66
		N Pratt	6	67	4				A Barna	4	3
								5	N Petrova	6	6

	First round							Second round							Third round							Quarterfinals
								6	J Capriati	6	6
	WC	J Schruff	6	6				WC	J Schruff	3	1
	Q	M Tu	1	1											6	J Capriati	5	6	6
	LL	J Vakulenko	3	3											17	M Sharapova	7	4	1
		P Mandula	6	6					P Mandula	4r
		D Safina	1	6	3			17	M Sharapova	5
	17	M Sharapova	6	1	6																	6	J Capriati	6	6
	13	P Schnyder	6	6																		4	A Myskina	3	2
		D Hantuchová	2	2				13	P Schnyder	6	6
	Q	E Gagliardi	6	6				Q	E Gagliardi	3	4
		C Black	1	3											13	P Schnyder
	Q	J Kostanić	77	6											4	A Myskina	w/o
		T Pisnik	64	3				Q	J Kostanić	2	4
								4	A Myskina	6	6

	First round							Second round							Third round							Quarterfinals
								7	E Dementieva	6	3	6
	WC	S Gehrlein	3	5				Q	S Cohen-Aloro	4	6	2
	Q	S Cohen-Aloro	6	7											7	E Dementieva	2	77	4
	Q	Z Yan	77	5	2										10	S Kuznetsova	6	65	6
		E Bovina	65	7	6				E Bovina	2	0
	WC	M-G Mikaelian	3	1				10	S Kuznetsova	6	6
	10	S Kuznetsova	6	6																		10	S Kuznetsova	77	3	1
	14	C Martínez	3	6	4																	2	A Mauresmo	65	6	6
		M Sánchez Lorenzo	6	3	6				M Sánchez Lorenzo	6	4	3
		A Parra Santonja	4	0					D Chládková	2	6	6
		D Chládková	6	6												D Chládková	1	2
	Q	M Paštiková	4	3											2	A Mauresmo	6	6
		G Dulko	6	6					G Dulko	1	2
								2	A Mauresmo	6	6

• Main and qualifying draws