This paper argues that the past decade has seen significant changes in the nature of medical work in general practice in the UK. Increasing pressure to use normative clinical guidelines and the move towards explicit quantitative measures of performance together have the potential to alter the way in which health care is delivered to patients. Whilst it is possible to view these developments from the well-established sociological perspectives of deprofessionalisation and proletarianisation, this paper takes a view of general practice as work, and uses the ideas of Lipsky to analyse practice-level responses to some of these changes. In addition to evidence-based clinical guidelines, National Service Frameworks, introduced by the UK government in 1997, also specify detailed models of service provision that health care providers are expected to follow. As part of a larger study examining the impact of National Service Frameworks in general practice, the response of three practices to the first four NSFs were explored. The failure of NSFs to make a significant impact is compared to the practices' positive responses to purely clinical guidelines such as those developed by the British Hypertension Society. Lipsky's concept of public service workers as 'street-level bureaucrats' is discussed and used as a framework within which to view these findings.