|Category||World Series (Free Week)|
|Draw||32S / 16D|
|Surface||Carpet / indoor|
|Michael Stich |
|Anders Järryd / Gary Muller |
The 1991 CA-TennisTrophy was a men's tennis tournament played on indoor carpet courts at the Wiener Stadthalle in Vienna in Austria and was part of the World Series of the 1991 ATP Tour. It was the 17th editon of the tournament and was held from 14 October through 21 October 1991. First-seeded Michael Stich won the singles title.
- It was Stich's 5th title of the year and the 10th of his career.
- It was Järryd's 5th title of the year and the 52nd of his career. It was Muller's 2nd title of the year and the 5th of his career.