The Centro Internacional de Agricultura Tropical (CIAT), Colombia, and the Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), France, are collaborating to improve upland-rice populations for Latin America. The main goal is to develop populations for use as sources of new progenitors and fixed lines with the specific traits required by the region's national programs. To achieve this, the international centers introduced, characterized, and developed new gene pools and populations from which lines were derived, showing the potential of the method to produce improved populations that can act as sources for new varieties. Two examples of using recurrent selection were (1) for reaction to acid soils, evaluation and selection were based on S 0:2 families; and (2) for the diseases rice blast and "hoja blanca" (white leaf), mass selection of sterile and fertile S. plants was used, selecting for both sexes. For both cases, results were impressive and highlighted the potential of recurrent selection for rice. Future work will continue with population improvement for the traits mentioned, include studies to determine genetic gains, and continue supporting national programs in advancing segregating generations and creating new populations.