All organisms - from bacteria to mammals – seem to employ no more than 22 amino acids to build their proteins. Thus, proteins containing non-natural synthetic amino acids are of great interest for basic research and biotechnology. They would expand the options of protein engineering and biocatalysis. However, the directed incorporation of non-natural amino acids into proteins remains a formidable challenge. Recent years saw the development of different methods to this end: Feeding non-natural amino acids to auxotrophic cells, the engineering of orthogonal systems into cellular protein biosynthesis, and cell-free biosynthesis have proven useful for the production of such proteins. The one-day symposion, organised by the DECHEMA working group on novel bio-production systems, will focus on recent advancements in the production and the application of these artificial proteins.