Plants modified by recombinant DNA (rDNA) have been known since 1983 when three research teams independently reported the first stable integration of foreign DNA into plant cells and the regeneration of genetically modified plants. By 1987 rDNA-modified crop species were available that warranted field evaluation of traits conferred by the new genes. By the end of 1992 more than 40 species of rDNA-modified food and fiber crops will have been described and almost 600 field tests of rDNA-modified plants will be completed or in progress in more than 20 countries around the world. Many of these tests will involve plants of potential commercial value since they represent genetic improvements in disease or pest resistance, hybridization technologies, or value-added food traits such as nutritional or processing enhancements. The field tests evidence the substantial public and private commitments that have been made to agricultural biotechnology. They also provide tangible proof of very successful technology transfer from basic plant molecular biology laboratories to problem-solving research programs that should help ensure agricultural sufficiency into the next century.