Abstract: With the sequencing of genomes, attention has turned to the structures and functions of proteins. Although cell-based expression systems have been widely used, they have certain limitations in view of the quality, quantity, or high-throughput production of proteins. Many of those limitations can be circumvented by the use of cell-free translation systems. Among such systems, the wheat germ-based system is of special interest for its eukaryotic nature; it has the significant advantage of producing eukaryotic multi-domain proteins in folded state. In addition, wheat seeds are available at low cost and may have minimal problems in biopollution and ethical issues because it is a foodstuff. Here I review how the highly efficient cell-free expression system is built and introduce its application to today’s functional and structural biology. (Reference: Current Opinion in Biotechnology 2006, 17: 1-8.)