Polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyethersulfone (PES) were implanted with 200 keV boron ions at three different doses. PS was also implanted with 100 keV boron. A nanoindentation technique and reciprocating sliding wear tests were used to characterize mechanical properties of the implanted polymers. The results showed that hardness increased with increasing dose as well as increasing energy. The percentage increase in hardness was reduced with increasing complexity of the side groups although absolute hardness values were higher. With increasing complexity of the main backbone, polymer chain, the percentage increase in hardness as well as numerical hardness values were lower. These effects were attributed to the relative contributions of cross-linking and chain scission which were viewed as competing processes. Wear tests showed that in general, a lower or intermediate implant dose yielded the best improvement in wear resistance. No specific trends were observed for relating friction coefficient values and improved wear resistance. The results indicate that wear is a complex phenomenon which has a sensitive dependence on hardness and elastic properties of the mating surfaces.