This thesis is drawn from an ongoing, large-scale project of implementing Electronic Patient Record (EPR) at the national hospital in Norway. The fact that the notion of the electronic record dates back to the 60 s and 70 s, illustrate how highly challenging the transformation to digital record has been. The overall aim in this study is to develop a deeper understanding of the socio-technical aspects of the complexities and challenges emerging from the implementation of the EPR and to study how to manage a gradual transition to digital patient record. The analysis leads me to view the transition process as a mutual, dynamic, and reflexive transformation of both information infrastructures and situated practices of use. The study shows us how implementing an electronic record changes not only one element in this interplay between the paper-based and the electronic record, but also the work practices that were developed around it. In addition, I will illustrate how the medical record and the work practice are not singular elements, but rather part of a large heterogeneous socio-technical network that includes artefacts, tools, people etc.