1990 Yugoslav Open
Date	14–20 May
Edition	1st
Category	World Series
Draw	32S / 16D
Prize money	$175,000
Surface	Clay / outdoor
Location	Umag, Yugoslavia (current Croatia)
Champions
Singles
Goran Prpić[1]
Doubles
Vojtěch Flégl / Daniel Vacek[2]
Croatia Open · 1991 →

The 1990 Yugoslav Open was a men's tennis tournament played on outdoor clay courts in Umag, Yugoslavia that was part of the World Series (Designated Week) of the 1990 ATP Tour. It was the first edition of the tournament and was held from 14 May until 20 May 1990. No.1 seed Goran Prpić won the singles title.^[3]

Finals

Singles

Goran Prpić defeated Goran Ivanišević, 6–3, 4–6, 6-4

• It was Prpić's only ATP singles title of his career.

Doubles

Vojtěch Flégl / Daniel Vacek defeated Andrei Cherkasov / Andrei Olhovskiy, 6–4, 6–4

• It was Flégl's first doubles title of his career. It was Vacek's first doubles title of his career.