Against a background of government calls for a radical change in the way the medical workforce is planned and trained, the concept of skill mix seeks to match clinical presentation to an intervention based on an appropriate level of skill and training. Health economics is not the only framework within which these changes can be analysed. However unless the economic issues are thought through clearly there is a danger that resources may be used inefficiently. The aims of this paper are to outline the economic issues in the area of doctor/nurse skill mix and the problems of obtaining correct solutions from the perspective of efficiency. It concludes by offering a pragmatic framework which can facilitate decisions in this area. Although this paper is written from the perspective of primary care, it is equally relevant to skill mix in the secondary care sector.