||Wheat varieties from South America have been used in many breeding programs, including CIMMYT's Wheat Program. They have played a major role in widening the adaptation of new varieties and increasing their resistance to diseases and environmental stresses. Seven years ago, when CIMMYT's Southern Cone Program was started, it was considered useful to compile a list of wheat varieties released by national programs in the region. The purpose of the list is to facilitate the exchange of more exact information among wheat researchers working with these materials and to assist them in their notetaking and record-keeping activities. However, due to other priorities, data collection did not begin until 1983. In the meantime, various published sources were consulted and varietal releases were updated. During the compilation process, it was observed that some of the information from various sources did not coincide. As a result, several draft lists were made up and subsequently corrected by various cooperators. However, there are still many old varieties with incomplete information, though an effort has been made to provide complete information on widely used and/ or new varieties. In this bulletin, the final result of the compilation efforts, varietal crosses have been expressed using the new system of slashes and numbers recently adopted by CIMMYT.