Background: It has been shown that EDI can yield positive effects within companies. Which effects are possible for a company to direct assign to the introduction of EDI and is it possible to estimate the total effect. Purpose: The purpose of this study is to estimate and analyze the effects of using EDI in electronic business. We also want to contribute with a model for measure and estimate the effects of EDI. Accomplishment: We have studied literature concering EDI and realized a preliminary studie in form of interviews with experts to establish deeper knowledge of EDI. We have also tried to estimate the effects obtained in companies in three different businesses, power, government and transport industry. Result: To obtain as good effects as possible it is important that the co- oporation is built on trust and engagement. Before implementing the EDI-system a thorough overhaul of the processes in the company should be done, involving both the top managers and the staff. Internet can be used to achieve minimal cost and it is important to limit the information sent by EDI to only send the information demanded. Finally companies also should mediate the advantages of EDI inside the organisation to make the co-operators realize the good effects obtained by EDI.