Outlines the nature and content of unit portfolios developed at Sheffield Hallam University, in response to national quality assurance initiatives and the enhanced status accorded to credit-bearing units of study which constitute the basic building blocks of courses and programmes. Draws on the experience of introducing unit portfolios. Argues that the time and effort involved in compiling and maintaining them need to be justified, with respect to quality assurance, planning, unit management, staff development and the diffusion of innovation. Considers their advantages including ease of access; greater transparency in delivery methods and the responsibilities of unit leaders; and incorporation of best practice. Examines the tensions to which their introduction and potential roles give rise and the arguments of those who are opposed to developments of this kind, such as the opportunity cost of compiling them and the perceived erosion of academic freedom.