The role of patents in industrialization and development has been a contentious issue for a long time. In the mid-nineteenth century, Europe saw intense political debate and widespread opposition to patent monopolies. Between 1850 and 1875, advocates for free trade called for radical reforms and even the abolition of patents across the continent. Patents again became a focal point of controversy during the post-World War II era. Even when intellectual property rights were widely accepted as a technological policy, developing countries began questioning the usefulness and imbalances of the ‘international patent system’ established with the Paris Convention of 1883. The rise of Import Substitution Industrialization (ISI) policies during the 1940s and 1950s was the result of intellectual and policy debates on the need to achieve industrial autonomy and regulate the transfer of capital-intensive technologies (manufacturing machinery, chemicals, automobile production) in countries such as Mexico, Argentina, and Brazil. Although the ISI strategy had limited success, it inspired new views on the role of technology in development and, more precisely, on the role of patents among developing economies during the 1960s and 1970s. With the new impetus of policy reform, Mexico, Brazil, and the members of the Andean Pact started challenging the international framework governing patent rights as a strategy to reduce dependency on foreign technologies. This chapter examines the competing interpretations of the relationship between patents, technology transfer, and economic development during the ‘age of international development.’ Specifically, it focuses on how the United Nations Conference on Trade and Development (UNCTAD) emerged as a central forum for debating intellectual property rights among experts and staff members. Despite UNCTAD’s efforts to radically reinvent the ‘international patent system,’ the demands of developing countries were ultimately unsuccessful. However, this chapter emphasizes the value of studying diplomatic and policy documents that envision alternative technological futures for the developing world.