High reliability organisations operate safely in situations of high risk by organising for collective mindfulness. They do so through five ongoing processes geared towards anticipating, containing, and making sense of the unexpected. The five processes are: preoccupation with failure, reluctance to simplify interpretations, sensitivity to operations, commitment to resilience, and deference to expertise. The theory of collective mindfulness builds on Hutchins's theory of distributed cognition (the 'collective mind' of ship navigation teams) and on Langer's theory of mindfulness about individuals' interpreting information in context. However, in the theory of collective mindfulness, attention is paid not to individual cognition or decision making, but to collective processes of sensemaking emerging from individuals' interactions in dealing with an equivocal environment. In health informatics, the theory of collective mindfulness can be used to explain health information technology (IT) development and implementation, across its life cycle, and inform guidance towards mindful management of IT projects. For example, applied to a case of electronic health record implementation in a hospital context, the theory explains how mindful management of the sense-making challenges of post-roll out adaptation processes contributes to a 'successful' IT project. Further, the theory challenges a static and linear understanding of success (or failure) of health IT initiatives, supporting instead an argument for outcomes - be it reliability and safety, or IT project success - as collective, complex and dynamic achievements of mindful organising practices.