This paper explores the relationship between organisational knowledge, organisational culture, and Process Based Systems (PBS), in the U.K. National Health Service (NHS). Links between PBS and organisational culture have been observed before(Perry, 2003); the contribution made by PBS to organisational knowledge has also been suggested (Perry, 2004). However, links between organisational knowledge and organisational culture in the NHS have not been widely studied. A qualitative study of these links across clinical functions has been used in conjunction with a literature review to consider in particular the use of tacit knowledge and the role that might be played by PBS in mediating and sharing this "embedded" or experiential form of knowledge. While there may be some opportunity for "externalisation" (Nonaka, 1994) - the conversion of tacit to explicit knowledge, this paper argues that PBS may also contribute to "socialisation" - the direct generation of tacit knowledge by tacit knowledge.