The CIMMYT Wheat Program is dealing with the germplasm improvement of four crops: bread wheat, durum wheat, triticale, and barley. The following is a brief description of the Wheat Program's major domestic and international breeding and testing nurseries. The purpose here is to acquaint visiting scientists and trainees with the role of eac'l nursery in the overall breeding scheme, how each nursery is planted, and what interrelationships may exist among various wheat, barley, and triticale nurseries, both domestic and international. This is not an attempt to explain CIMMYT breeding philosophies, nor is it a complete listing of all the nurseries or locations with which CIMMYT works.