This report documents the number and types of maize varieties and hybrids released by public breeding programs between 1966 and 1997, describes the varieties and hybrids marketed by public seed agencies and private companies in Latin America in 1997, analyzes recent trends in commercial maize seed sales, estimates the area planted to improved maize germplasm in 1966, and discusses factors that have influenced adoption. The authors find that the primary locus of maize breeding research has shifted to the private sector, the private sector now dominates commercial maize seed production, and the maize seed industry in Latin America has become increasingly concentrated. Although the area planted to improved maize germplasm continues to increase, adoption has been uneven. The use of CIMMYT materials has been extensive in public has well as private sector breeding programs, and total area shown to CIMMYT-related materials continues to increase.