Functional flexibility has been advocated as a mechanism for improving efficiency and service quality and is, it is argued, especially appropriate to service environments. In recent years the UK public health service has been subject to an ongoing programme of reform, designed to modernize the way in which health services are provided. A central feature of the reform involves breaking down traditional boundaries and the re‐organization of work roles. This article is concerned with examining the implementation of functional flexibility in three health‐care settings. Case‐study data are presented, focusing on the responses of employees and managers to initiatives to work more flexibly. For managers the implementation achieved efficiency gains and improvements to service quality, in spite of some resistance from employees. For employees the outcomes were more mixed. There was evidence of ‘humanization’ through greater job variety, challenge and access to training, but there were also costs in terms of intensification, role confusion and stress. The implications of these findings both for understanding the issues raised by the use of functional flexibility and for the implementation of policies in the NHS involving job redesign are discussed.