It is widely accepted that the establishment of interoperability of firm?s IS with the ones of other cooperating firms (e.g. customers, suppliers, business partners) can generate significant business value. However, this has been only to a very limited extent empirically investigated. This paper contributes to filling this research gap by presenting an empirical study of the effect of IS interoperability on the four business performance dimensions/perspectives proposed by the Balanced Scorecard approach (financial, internal business processes, customers, learning and innovation). In particular, we examine the effects of adopting three different fundamental types of IS interoperability standards differing in the level of detail and applicability: XML, industry-specific standards and proprietary standards. Our study is based on a large dataset from 14065 European firms (from 25 countries and 10 sectors) collected through the e-Business Watch Survey of the European Commission. It is concluded that all these three examined types of IS interoperability standards increase considerably the positive impact of firm?s IS on the above four business performance perspectives/dimensions; however, their effects differ significantly. The adoption of industry-specific interoperability standards has the highest impact on business performance, while XML and proprietary standards have similar lower impacts. These conclusions provide valuable empirical evidence of the multidimensional business value generated by IS interoperability and its strong dependence on the type of IS interoperability standards adopted.