This case study of the organizational structure of the Brazilian Literacy Movement (MOBRAL) describes the various organizational changes made as the mediating agency attempted to develop a large-scale national program within the existing social structure. Steps in the organization's development are traced from: (1) Beginnings in 1970 under the country's Ministry of Education and Culture as a flexible, decentralized national system with coordinators in the country's 22 states, through (2) some consolidation of structure in the central office to better manage the widespread activities, to (3) successful working operation at the end of the third year with five million students enrolled in classes in all of Brazil's 3,953 municipalities. Conclusions are drawn regarding the relative advantages and disadvantages of closed and open organizational systems with respect to the flexibility built into the MOBRAL structure. Brief comments are also included on MOBRAL as a model of organization and management for other institutions. Various charts depict the MOBRAL structure at national, state, and municipal levels. (JT)