Singles
1999 Grolsch Open
Final
Champion	Younes El Aynaoui
Runner-up	Mariano Zabaleta
Score	6–0, 6–3
Details
Draw	32
Seeds	8
Events
Singles Doubles
← 1998 · Dutch Open · 2000 →

Magnus Norman was the defending champion, but the fifth seeded Swede lost in the first round to qualifier Adrian Voinea. Younes El Aynaoui won in the final 6–0, 6–3 against number three seed Mariano Zabaleta and captured the second title of his professional career.

Champion seeds are indicated in bold while text in italics indicates the round in which that seed was eliminated.

	Semifinals							Final
	8	Marat Safin	1	4
	6	Younes El Aynaoui	6	6
								6	Younes El Aynaoui	6	6
								3	Mariano Zabaleta	0	3
	3	Mariano Zabaleta	3	7	7
	2	Nicolás Lapentti	6	5	5

	First round							Second round							Quarterfinals							Semifinals
	1	D Hrbatý	2	3
		A Di Pasquale	6	6					A Di Pasquale	77	6
	Q	A Vinceguerra	1	65					A Pavel	65	2
		A Pavel	6	77												A Di Pasquale	67	6	4
		G Gaudio	4	6	6										8	M Safin	79	0	6
		S Sargsian	6	2	2				G Gaudio	4	64
		J van Lottum	6	3	5			8	M Safin	6	77
	8	M Safin	2	6	7																	8	M Safin	1	4
	4	F Meligeni	6	77																		6	Y El Aynaoui	6	6
	WC	A Berasategui	3	61				4	F Meligeni	6	77
		F Vicente	62	4				SE	A Portas	3	63
	SE	A Portas	77	6											4	F Meligeni	2	4
	SE	J Tarango	4	63											6	Y El Aynaoui	6	6
		K Alami	6	77					K Alami	6	1	1
		S Koubek	66	3				6	Y El Aynaoui	1	6	6
	6	Y El Aynaoui	78	6

	First round							Second round							Quarterfinals							Semifinals
	5	M Norman	6	64	66
		A Voinea	4	77	78				A Voinea	6	3	1
		M Gustafsson	2	7	6				M Gustafsson	3	6	6
		B Ulihrach	6	5	1											M Gustafsson	63	3
		M Puerta	5	1											3	M Zabaleta	77	6
		F Squillari	7	6					F Squillari	5	4
	Q	R Sluiter	3	6	61			3	M Zabaleta	7	6
	3	M Zabaleta	6	4	77																	3	M Zabaleta	3	7	7
	7	A Medvedev	7	6																		2	N Lapentti	6	5	5
	WC	P Haarhuis	5	3				7	A Medvedev	2	3
		S Schalken	2	6	4				H Arazi	6	6
		H Arazi	6	0	6											H Arazi	6	5	3
		C Ruud	6	5	7										2	N Lapentti	2	7	6
	WC	P Wessels	3	7	5				C Ruud	5	3
	Q	M Rodríguez	3	2				2	N Lapentti	7	6
	2	N Lapentti	6	6

• ATP main draw