Cyclic peptides offer great potential for drug development: their discovery can be rapidly achieved using contemporary display screening techniques, they exhibit very high target affinity and specificity, they are amenable to chemical synthesis, they have unique and tailorable pharmacokinetic profiles, and they can (in some cases) be orally available and membrane-permeant. For these reasons, the last decade has seen enormous growth in cyclic peptide research in the pharmaceutical sector, and their clinical development is now proceeding along multiple lines. This is generating new challenges for peptide synthetic methodologies, which will need to be addressed over coming years.