The 1990 Philips Open was a men's tennis tournament played on outdoor hard courts at the Hotel Transamerica in São Paulo, Brazil that was part of the World Series category of the 1990 ATP Tour.

It was the fifth edition of the tournament and took place from 22 October through 28 October 1990.

Seventh-seeded Robbie Weiss, who entered the main draw as a lucky loser, won the singles title.

[3] Robbie Weiss defeated Jaime Yzaga 3–6, 7–6(9–7), 6–3 Shelby Cannon / Alfonso Mora defeated Mark Koevermans / Luiz Mattar 6–7, 6–3, 7–6