Electronic Data Interchange (EDI) holds the potential to improve contemporary business operations, which are redefined frequently based on the demands of global competition. There are numerous EDI systems, which an enterprise can choose to adopt in order to meet its needs and goals. International literature demonstrates a variation of views regarding the adoption of new technologies, which differ according the size of each organization along with internal and external impediments and determinants. The use of EDI worldwide has gained a positive acceptance by commercial companies, industries and service providers, followed by rapid adoption mainly in the processes of large organizations. Conversely, the predictions of previous years’ studies have not been materialized to the expected extent. In Greece in particular, there is low penetration and a reluctance to adopt EDI technologies by Small and Medium Enterprises (SMEs). This study is based on the theoretical framework of Technology, Organization and Environment (TOE). A qualitative multiple case study research design has been used, in order to provide further insights on the factors that affect the decision of Greek SMEs in adopting EDI technologies. The significance of the perceived direct and indirect benefits, the effects of the perceived financial cost and technical competence and the importance of industry and government pressure on corporate level, are analyzed and discussed. An empirical support of the low penetration of EDI in the Greek SMEs' community is also provided. This research contributes in the existing knowledge about EDI adoption decisions regarding Greek SMEs by providing a variation of views, further insights on how Greek SMEs behave and react during the current economic recession and a new cost factor that emerged within the analysis of multiple cases. Avenues for future research are recommended in order to expand this study's findings in the field of corporate IT innovation.