This paper uses a long term ethnographic study of the design and implementation of an electronic patient records (EPR) system in a UK hospital Trust to consider issues arising in the multi-faceted process of integration when a customizable-off-the-shelf (COTS) system is configured and deployed in a complex setting. The process involves trying to artfully work out how disparate technologies integrate with existing and evolving patterns of work within developing regulatory requirements. We conclude by suggesting ways in which ethnographic interventions and user involvement may be timed and targeted to aid in achieving this process. Categories And Subject Descriptors H.5.3 [Information interfaces and presentation]: Group and organization interfaces - Computer-supported cooperative work, organization design; J.4 [Computer applications]: Social and behavioural sciences - Sociology; D.2 [Software] Software