Organizations striving to compete in today’s harsh economic environment are forced to continuously innovate to retain competitiveness over time. The use of inter-organizational systems (IOS) is one way for organizations to gain competitive advantage. This paper attempts to investigate the adoption of IOS by means of a controlled field-experiment on organizational level. Relevant scientific literature on this topic largely agrees that two main factors of influence – circumstantial information, and institutional pressure – are assumed to have a strong influence on adoption intention of organizations. By conducting a field experiment across 504 business partners of a larger German organization, we find evidence for the relationship between institutional pressure and IOS adoption, while no support is found for the relation between circumstantial information and IOS adoption.