The population of many Latin American countries is having increasing difficulty in accessing needed medicines due to the rise in their unitary cost and the growing number of poor in most countries of the region. A number of countries have taken steps to increase access to pharmaceuticals and have had different levels of success. This article reports on two country-wide programmes: the AIDS programme in Brazil, which has been judged as being highly successful, and the Remediar programme that has been implemented recently in Argentina. Both programmes have significantly increased access to needed pharmaceuticals, and Argentina has done it in a record time. In the discussion, we suggest that pharmaceutical interventions are successful when there is a firm political commitment, they are comprehensive, include the participation of civil society, and use a combination of methods to control the rising cost of medicines, including centralized international competitive bidding processes for drug procurement and reliance on multi-source drugs.