We examine how important social and technical choices become part of the history of a CBIS and embedded in the social structure which support its development and use. These elements of a CBIS can be organized in specific ways to enhance its usability and performance. Paradoxically, they can also constrain future implementations and post-implementations. We argue that CBIS developed from complex, interdependent social and technical choices should be conceptualized in terms of their institutional characteristics, as well as their information processing characteristics. The social system which supports the development and operation of a CBIS is one major element whose institutional characteristics can effectively support routine activities while impeding substantial innovation. Characterizing CBIS as institutions is important for three reasons: 1) the usability of CBIS is more critical than the abstract information processing capabilities of the underlying technology; 2) CBIS that are well-used and are based on stable social structures of support (infrastructures) which are more difficult to replace than those with less developed social structures and fewer participants; and 3) CBIS vary from one social setting to another according to the ways in which they are organized and embedded in organized social systems. These ideas are illustrated with the case study of a failed attempt to convert a complex inventory control system in a medium-sized manufacturing firm.