Cell-free protein technologies are becoming alternatives to cell-based methods for proteomic and biotechnology applications. We have developed two powerful protein technologies by novel exploitation of cell-free expression systems. They are termed (i) ribosome display (1, 2) and (ii) protein in situ array (3). Both technologies rapidly convert genetic information into proteins without the need for E. coli cloning. While ribosome display permits direct selection and identification of protein binders from large PCR libraries, protein in situ array produces immobilised proteins in parallel through a single-step on-chip synthesis. An integration of these technologies would allow library vs library screening for high-throughput identification of protein interacting partners in vitro.