This paper aims at articulating a conceptual framework for monitoring equity in health and healthcare. The focus is on four main questions: What is health equity? What is monitoring? What are the essential components of a system for monitoring health equity? and Why monitor health equity? Monitoring equity in health and healthcare requires comparing indicators of health and its social determinants among social groups with different levels of underlying social advantage, i.e. groups who occupy different positions in a social hierarchy. A framework is presented for formulating the key questions, defining the social groups to be compared, and selecting the health indicators and measures of disparity that are fundamental to monitoring health equity. Although monitoring health equity is a scientific endeavour, its fundamental objective is guided by values; technical challenges should be addressed as part of a broader strategy to confront the political obstacles to greater equity.