Health equity is one of the main avowed objectives of public health policy across the world. Yet economic evaluations in public health (like those in health care more generally) continue to focus on maximizing health gain. Health equity considerations are rarely mentioned. Health economists rely on the quasi-egalitarian value judgment that 'a QALY is a QALY'--that is QALYs are equally weighted and the same health outcome is worth the same no matter how it is achieved or to whom it accrues. This value judgment is questionable in many important circumstances in public health. For example, policy-makers may place rather little value on health outcomes achieved by infringing individual liberties or by discriminating on the basis of age, sex, or race. Furthermore, there is evidence that a majority of the general public wish to give greater weight to health gains accruing to children, the severely ill, and, to a lesser extent, the socio-economically disadvantaged. This paper outlines four approaches to explicit incorporation of equity considerations into economic evaluation in public health: (i) review of background information on equity, (ii) health inequality impact assessment, (iii) analysis of the opportunity cost of equity, and (iv) equity weighting of health outcomes. The first three approaches can readily be applied using standard methods of health technology assessment, where suitable data are available; whereas approaches for generating equity weights remain experimental. The potential benefits of considering equity are likely to be largest in cases involving: (a) interventions that target disadvantaged individuals or communities and are also relatively cost-ineffective and (b) interventions to encourage lifestyle change, which may be relatively ineffective among 'hard-to-reach' disadvantaged groups and hence may require re-design to avoid increasing health inequalities.