1991 CA-TennisTrophy
| 1991 CA-TennisTrophy | |
|---|---|
| Date | 14–21 October1 |
| Edition | 17th |
| Category | World Series (Free Week) |
| Draw | 32S / 16D |
| Prize money | $125,000 |
| Surface | Carpet / indoor |
| Location | Vienna, Austria |
| Venue | Wiener Stadthalle |
| Champions | |
| Singles | |
 Michael Stich [1] | |
| Doubles | |
 Anders Järryd /  Gary Muller [2] | |
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.
Finals
Singles
Michael Stich defeated 
Jan Siemerink 6–4, 6–4, 6–4
- It was Stich's 5th title of the year and the 10th of his career.
Doubles
Anders Järryd / Gary Muller defeated 
Jakob Hlasek / 
Patrick McEnroe 6–4, 7–5
- 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.