This paper is part of a series of research papers prepared for the Working Group on Health and International Economy of the Commission on Macroeconomics and Health (CMH). The Commission was set up in January, 2000, by the Director General, World Health Organisation, under the Chairmanship of Prof. Jeffrey Sachs. As a member of the
CMH and Co-chairperson of this Working Group, I have had the privilege of commissioning research papers on issues of importance for health and the international economy. This revised version of the paper by John Barton, Professor, Stanford Law School, addresses the problem of affordable access to patented medicines by exploring the mechanism of differentiated pricing of patented products between the developed and the developing countries and the associated requirements of market segmentation.