This paper will outline a research methodology informed by theorists who have contributed to actor network theory (ANT). Research informed from such a perspective recognises the constitutive role of accounting systems in the achievement of broader social goals. Latour, Knorr-Cetina and others argue that the bringing in of non-human actants, through the growth of technology and science, has added immeasurably to the complexity of modern society. The paper "sees" accounting and accounting systems as being constituted by technological "black boxes" and seeks to discuss two questions. One concerns the processes which surround the establishment of "facts", ie. how "black boxes" are created or accepted (even if temporarily) within society. The second concerns the role of existing "black boxes" within society and organisations. Accounting systems not only promote a particular view of the activities of an organisation or a subunit, but in their very implementation and operation 'mobilise' other organisational members in a particular direction. The implications of such an interpretation are explored in the paper. Firstly through a discussion of some of the theoretic constructs that have been proposed to frame ANT research. Secondly an attempt is made to relate some of these ideas to aspects of the empirics in a qualitative case study. The case site is in the health sector and involves the implementation of a casemix accounting system. Evidence from the case research is used to exemplify aspects of the theoretical constructs.