There are a number of car renting companies which offer services not only inside of Vienna but all through Austria, and also the Schengen territory.
Quite popular is the Tiger Car Rental Company, claiming to provide the lowest hire rates:
Check out their packages at:
Other major car rental companies are:
Avis: Opernring 3-5 (tel. 01/587-62-41)
Budget Rent-a-Car: Hilton Air Terminal (tel. 01/714-6565)
Hertz: Karntner Ring, 17 (tel. 01/512-8677).