The controlled polymerisation of a bulky, peptide-based monomer was investigated. The cyclic beta-sheet forming decapeptide gramicidin S was modified with a methacrylate handle and subsequently polymerised via atom transfer radical polymerisation (ATRP), to yield a well-defined gramicidin -S-containing polymer. The secondary structure of the peptide moiety was retained within the resulting polymer, as indicated by IR spectroscopy. This is the first example of the use of ATRP to create a synthetic polymer with a cyclic peptide as a side chain.