1990 Mercedes Cup – Singles

Martín Jaite was the defending champion, but lost in the second round to Karel Nováček.

Goran Ivanišević won the title by defeating Guillermo Pérez Roldán 6–7(2–7), 6–1, 6–4, 7–6(7–5) in the final.

Seeds
All seeds received a bye into the second round. • # 🇪🇨 Andrés Gómez (third round)

• # 🇦🇹 Thomas Muster (second round, retired)

• # 🇪🇸 Emilio Sánchez (semifinals)

• # 🇦🇷 Martín Jaite (second round)

• # Andrei Chesnokov (third round)

• # 🇺🇸 Jim Courier (second round)

• # 🇪🇸 Juan Aguilera (second round)

• # 🇫🇷 Guy Forget (second round)

• # 🇦🇷 Guillermo Pérez Roldán (final)

• # Goran Ivanišević (champion)

• # Carl-Uwe Steeb (second round)

• # 🇫🇷 Henri Leconte (semifinals)

• # Petr Korda (second round)

• # Marc Rosset (second round)

• # 🇸🇪 Mats Wilander (second round)

• # 🇦🇹 Horst Skoff (quarterfinals)