The more than 40 international organizations located in Vienna appear as an important economic factor. In 2017 they spent nearly 860 million Euros in Austria for personnel and non-personnel expenses. A large amount of these expenses has an impact on the Austrian economy in terms of value added, employment and tax revenues. In addition, there are economic effects from diplomatic representations, from international schools as well as from events directly related to the international organizations residing in Austria. In this study carried out on behalf of the Federal Ministry for Europe, Integration and Foreign Affairs the IHS has analyzed the economic effects of international organizations (direct, indirect and consumption- as well as investment-induced) by making use of its multiregional input-output model.