Our understanding of disease processes is rapidly increasing and an unprecedented number of macromolecular entities, including biopolymers such as nucleotides, peptides and proteins as well as synthetic polymers, are under investigation as therapeutic agents. The effective delivery of many of these therapeutic macromolecules to their target is constrained by their interaction with biological barriers, be this a feature of the macromolecule absorptive or dispositional processes, or indeed the need for the macromolecule to reach an intracellular target. Challenges faced in the effective delivery of macromolecule therapeutics to tissues, cells and subcellular compartments are considerable. The science underpinning the basic mechanisms of macromolecule interactions with biological barriers, through to the clinical translation of such entities into therapeutic agents serves as the focus of the Cellular Delivery of Therapeutic Macromolecules (CDTM) biennial international symposia series. The CDTM symposia have been held in Cardiff University since 2006 and a major objective for the organizers of this series, Drs Mark Gumbleton and Arwyn Jones, is for the symposia to serve the development of Early Stage Career researchers and to promote the inter-disciplinary collaborations necessary to make real progress in this field. All three symposia in the series CDTM2006, CDTM2008 and CDTM2010 have attracted the highest quality of international speakers and provided unique opportunities for delegates from around the world to interact with others engaged in this research area and to learn from more experienced attendees. For information on the CDTM series go to www.CDTM.cf.ac.uk.