This paper addresses the general question proposed by the call of this special issue: "What historical or contingent events and factors influence the creation of ICT standards, and in particular, their success or failure?" Based on a case study conducted over a period of three years in a Norwegian hospital on the standardization process of an electronic patient record (EPR), the paper contributes to the current discussion on the conceptualization of standard-making in the field of Information Systems. By drawing upon the concepts of logic of ordering adopted from actor-network theory and upon reflexivity and the unexpected side effects adopted from reflexive modernization, the paper makes three key contributions: (1) it demonstrates the socio-technical complexity of IS standards and standardization efforts; (2) it shows how complexity generates reflexive processes that undermine standardization aims; and (3) it suggests a theoretical interpretation of standardization complexity by using ideas from complexity theory and the theory of reflexive modernization. These research questions are addressed by offering an historical and contingent analysis of the complexity dynamics emerging from the case.