The 1990 German Open was a men's tennis tournament played on outdoor clay courts. It was the 84th edition of the Hamburg Masters (Hamburg Masters), and was part of the ATP Super 9 of the 1990 ATP Tour. It took place at the Rothenbaum Tennis Center in Hamburg, West Germany, from 7 May through 14 May 1990.
The men's field was headlined by ATP No. 3, Brussels, Stuttgart titlist, Australian Open, Monte Carlo quarter-finalist Boris Becker, Miami, San Francisco winner, recent Indian Wells finalist Andre Agassi and Tokyo Indoor winner and US Open semi-finalist Aaron Krickstein. Other top seeds were Estoril titlist Emilio Sánchez, Jay Berger, Andrés Gómez and Michael Chang.
Juan Aguilera defeated Boris Becker, 6–1, 6–0, 7–6(9–7)
Sergi Bruguera / Jim Courier defeated Udo Riglewski / Michael Stich, 7–6, 6–2