One-third of the world’s population lacks access to the most basic essential drugs. For the destitute sick in the developing world, the price of medicines can determine whether they will be treated. Patents drive drug prices up, the resultant monopoly status allowing the producer to charge whatever price the market will bear. The World Trade Organization Trade-Related Aspects of Intellectual Property Rights (TRIPS) Agreement, which provides 20 years’ patent protection for pharmaceuticals, also includes safeguards such as compulsory licensing, to ensure that countries can override patents whenever they are a barrier to access to medicines. Intense lobbying from the multinational pharmaceutical industry and some Western governments, however, has frustrated the use of these safeguards. Experience from South Africa, Thailand, Kenya and Guatemala shows the enormous pressures countries face in implementing the TRIPS Agreement in a manner that protects public health and underscores the vital role played by civil society in defending the right to access affordable medicines.