Changes to the technological landscape of the National Health Service (NHS) in the UK have often raised debates on information privacy and patient confidentiality. This has been especially pertinent in the context of HIV health services, where patient records have been historically segregated from hospital notes to protect confidentiality and account for the nature of the condition as a stigmatised terminal illness. However, as current anti-retroviral treatment extends life expectancy, HIV is increasingly managed in ways similar to other chronic conditions and integrated patient management has been proposed as best practice. This shift offers a unique opportunity to study reconfigurations of privacy and confidentiality practices from the perspective of data users. This thesis focuses on a technological integration project between the stand-alone systems used in two HIV specialist outpatient centres and the centralised Electronic Patient Records (EPR) of their respective NHS Hospital Trusts. The case study methodology draws on 46 semi-structured interviews with health and IT professionals, supplemented by an analysis of organisational documents and observation of work practices over a period of six months in the two clinics. In weaving together different theoretical concepts, this thesis contributes to an in-depth, empirically informed understanding of privacy and confidentiality practices in healthcare. Firstly, by looking at how HIV practitioners cultivate their professional identities at the intersection of general medical and HIV-specific confidentiality, this thesis argues that identity work is an important component in the reconfiguration of privacy practices. Secondly, this research draws attention to the role of political negotiations for privacy change, as HIV professionals and EPR developers came in conflict over the ethics of the technological integration project in the hospitals studied here. Thirdly, this thesis illustrates how confidentiality practices are shaped within the co-construction of information infrastructures and medical work, especially in relation to HIV normalisation. A number of implications for practice and policy also emerge from this study.