Shuttle breeding uses diverse ecological environments to develop improved varieties with higher adaptability. Alternate generations of early breeding materials are grown under different environments. The basis of shuttle breeding is cooperative research among nations and institutions. The benefit is increased breeding efficiency. Currently the shuttle breeding approach is being used to develop improved varieties of wheat-maize, and rice. In 1974, the International Center for Maize and Wheat Improvement (CIMMYT) and the Government of Brazil began shuttle breeding to develop wheat varieties tolerance of aluminum toxicity. In 1982, CIMMYT and China started a shuttle breeding program to develop wheat varieties resistant to wheat scob, with high yield potential and wider adaptability. In 1983, the China National Rice Research Institute (CNRRI) and the International Rice Research Inst., Los Banos, Laguna, Philippines (IRRI) initiated a shuttle breeding project to develop early-maturing rice varieties with high-yield, good grain quality, multiple resistance, and wide adaptability. This paper focuses on the shuttle breeding procedures followed in that project, the progress made, and the effect of selecting breeding materials under different ecological environments.