Supply and marketing co-operatives used to monopolize the entire rural distribution system in China. They purchased agricultural produce from and sold raw materials and consumer goods to peasants. However, their monopoly was threatened by the opening up of the rural economy during the economic reform. This article describes how, over the past decade, supply and marketing co-operatives have been undergoing rapid changes and have significantly outgrown their original role as rural distribution institutions. Now they provide comprehensive services such as transportation, storage, price information and technical assistance to peasants. They also help rural enterprises source raw materials and market finished products.