Company competitiveness often depends on key relationships with other companies and information tech-nologies play a critical role in supporting these relationships. Nevertheless, tools to analyse the impact of technology on businesses are in short supply. This article presents the results of research performed in companies in the mass consumer industry aimed at verifying the validity of a proposed model based on transaction costs, to be used for impact evaluation of inter-organizational systems in companies. The model, which takes into account different kinds of benefits, is applied in an exploratory way to the identification of benefits from using electronic data interchange systems as an e-commerce tool to support business to business relationships. Verification of the proposed model confirms its usefulness for the identification of benefits, mainly for those occurring at the inter-organizative level.