Initiating the use of Computerised information systems (CISs) has become a global trend, including in Taiwan. Although CISs sound promising for improving clinical effectiveness and efficiency, evidence demonstrating their actual benefits is still limited. How CISs influence nursing practice and professionalism is not widely known, and the actual implementation process is not well understood. Hence, this study explores (1) the impact of CISs on the role of nurses and their practice, (2) the context of developing and implementing CISs, and (3) the practice politics underlying the use of information technologies in a Taiwanese hospital. A single, embedded, qualitative case study was conducted. Data collection used multiple methods, combining elite interviews with nurse managers (n=13) and informatics staff (n=3), five focus groups with front-line registered nurses (n=25) and 47 hours of non-participant observation in six wards in the case-study hospital. Data analysis followed a thematic approach, comparing and contrasting patterns among multiple perspectives. Four major themes emerged from the analysis. Firstly, the development of CISs was a result of negotiated order and relied upon interdisciplinary collaboration. Through interdisciplinary interactions of negotiations, covert negotiations and renegotiations, the exercise of power and power imbalances were recognised. Secondly, a top-down approach was adopted in the implementation process. In order to move computerisation forward, head nurses acted as change agents in gaining compliance from nurses. Front-line nurses showed generally positive attitudes towards computerisation. Being daily system users, front-line nurses were relatively powerless and were compliant with the top-down implementation; however, they grumbled at the same time. Thirdly, through system design strategies to structure clinical activities and increase information transparency, CISs became helpful tools in achieving standardised practice, tightening up managerial surveillance and control and clearly defining employees' accountabilities. Finally, whilst convenience and efficiency were perceived as the results of computerisation, hardware problems and the burdens of the computerisation process created hidden work in nursing practice, which required nurses to care for computers whilst caring for patients. Through the lens of several social theories, the study findings indicated that power in developing and implementing CISs was not in the hands of the nursing profession. The findings manifested the disciplinary power of computer technology and also suggest that computerisation may de-skill the nursing profession which may reignite the technology and skilling debate. Although generally believed to facilitate performance efficiency, this study found that computer technology created unfavourable consequences, for example hidden work, which seems to be unrecognised in the literature. Computers became the nurses 'co-client' and consequently took time away from patient care so computerisation may not be as efficient and effective as expected. Finally, a qualitative case study was found to be an appropriate methodology to explore this complex issue comprehensively and holistically. However, this small, single case study was conducted in one location in Taiwan. More research is needed to verify the findings which may have significant implications for management, policy and practice.