Also, Vienna is a very popular tourist destination, especially in summer, we therefore advise that you book your accommodation well in advance of the congress.
Hotel booking for the congress can be made online through a secure server.
AUSTROPA INTERCONVENTION is the official appointed housing office and has made a pre-selection of centrally located hotels close to the conference venue or easily accessible with underground line U1 at best possible rates.
Rates are in Euro, per night and room and include breakfast, service and all taxes
See here for info about the different hotels.