This paper examines some of the difficulties in using QALY league tables in priority setting. Such tables sometimes are seen as being 'the' way to prioritise in health care and in particular, at present, with respect to priority setting among purchasers in the UK NHS. However the paper highlights the fact that the base on which such tables is built is small--relatively few studies in the English language using CUA have been conducted anywhere. Further, four issues which require handling with care are set out: (i) the relevant measure of cost in QALY league tables has to be restricted to health service resource use; (ii) the relevant measure of benefit in QALY league tables is clearly restricted to QALYs, thereby the utility of health gains and indeed the maximisation of the utility of health gains; (iii) in incorporating the results of CUA studies into QALY league tables there is a need for greater clarification on what the margin constitutes; and (iv) those who might use CUA results in QALY league tables need to ascertain whether the original context of the study will allow the results to be transferred to the local context of the decision maker. The paper suggests that there is a need to be quite clear what goal QALY league tables serve. The authors argue that the only legitimate (and clearly important) goal of QALY league tables is the maximization of the utility of health gains within a health service budget.(ABSTRACT TRUNCATED AT 250 WORDS)