The United Nations Technical Assistance Administration (TAA) was the world organization’s main body for development advice throughout the 1950s. In technical assistance, the UN found a global mission at a time when its peace and security functions seemed ineffective. Technical assistance experts preached the need for less developed countries to plan and modernize. This process has been studied with regard to American modernization theory, but the important role of the UN as an autonomous diplomatic actor has been less visible. The UN was a relatively acceptable source of technical assistance for many governments. Among them was Indonesia, which welcomed UN help for its State Planning Bureau. TAA aid to the Planning Bureau advanced the interests of both organizations but both failed to institutionalize themselves enough to survive the decade. Both, however, left important legacies: the TAA for UN development thinking, and the Planning Bureau for the Indonesian developmentalist state.