Biomaterials repair, reinforce or replace damaged functional parts of the (human) body. All mechanical and biological interactions between an implant and the body occur across the interface, which has to correspond as nearly as possible to its particular function. Much of the progress in adapting polymer materials for use in a biological environment has been obtained through irradiation techniques. For this reason the most recent developments in four key areas are reviewed in this special volume: (1) the analysis of the topology and the elemental composition of a functional surface, (2) the chemical modification of the surface which results in highly pure, sterile and versatile surfaces, (3) the sterilisation of implantable devices via ionising radiation and its possible effects on the structural mechanical properties of polymers, and (4) the radiation effects on living cells and tissues which are of particular importance for radiation protection and radiotherapy.