Singles
1990 Yugoslav Open
Final
Champion	Goran Prpić
Runner-up	Goran Ivanišević
Score	6–3, 4-6, 6–4
Details
Draw	32 (3WC/4Q)
Seeds	8
Events
Singles Doubles
Croatia Open · 1991 →

The first edition of the ATP tournament in Umag was held from 14 May until 20 May 1990.^[1]

Goran Prpić won the title by defeating Goran Ivanišević 6–3, 4–6, 6–4 in the final.^[2][3]

	Semifinals							Final
	1	Goran Prpić	7	7
		Horacio de la Peña	6	6
								1	Goran Prpić	6	4	6
								2	Goran Ivanišević	3	6	4
	5/WC	Andrei Cherkasov	3	7	4
	2	Goran Ivanišević	6	5	6

	First round							Second round							Quarterfinals							Semifinals
	1	G Prpić	6	6	6
	Q	E Masso	7	4	0			1	G Prpić	6	6
		M Tauson	6	4					D Perez	2	0
		D Perez	7	6											1	G Prpić	6	6
		R Azar	6	6												R Azar	4	4
	Q	P Dogger	2	3					R Azar	0	77	6
	WC	F Cancellotti	4	1				7	M Vajda	6	6	3
	7	M Vajda	6	6																		1	G Prpić	7	7
	3	M Koevermans	7	6																			H de la Peña	6	6
	WC	S Hiršzon	6	3				3	M Koevermans	6	3
		E Bengoechea	7	2	0				H de la Peña	7	6
		H de la Peña	5	6	6											H de la Peña	5	7	6
		N Marques	4	7	6										6	A Rahunen	7	6	1
		L Jönsson	6	5	3				N Marques	6	4
		G Bloom	5	4				6	A Rahunen	7	6
	6	A Rahunen	7	6

	First round							Second round							Quarterfinals							Semifinals
	5/WC	A Cherkasov	6	6
	Q	J Clavet	2	4				5/WC	A Cherkasov	6	6
		O Delaître	6	4					F Roig	3	4
		F Roig	7	6											5/WC	A Cherkasov	6	6
	Q	D Buljević	6	6												E Jelen	2	0
		J Anderson	3	4				Q	D Buljević	6	3	6
		E Jelen	6	3	6				E Jelen	2	6	7
	4	J Woehrmann	1	6	0																	5/WC	A Cherkasov	3	7	4
	8	T Tulasne	6	3	1																	2	G Ivanišević	6	5	6
		J Potier	3	6	6				J Potier	2	6	6
		C Saceanu	2	2					T Benhabiles	6	3	7
		T Benhabiles	6	6												T Benhabiles	4	6
		M Tabares	4	4											2	G Ivanišević	6	7
		F Luna	6	6					F Luna	2	3
		N Pereira	1	4				2	G Ivanišević	6	6
	2	G Ivanišević	6	6

• Official results archive (ATP)
• Official results archive (ITF)