1. Introduction There has recently been increasing interest in the applications of plasma processing in a variety of industrial fields. One of applications of organic plasma processing now in practical use is plasma treatment. One of the advantages of plasma treatment is the fact that it is surface limited (500-1000Å) so that only the surface properties can be changed without affecting the bulk properties. In view of the fact that surface reactions of plasma treatment are initiated by plasma-induced surface radicals, study of the resulting radicals is of utmost importance for understanding of the nature of plasma treatment. Thus, we have undertaken plasma-irradiation of a wide variety of polymers, synthetic and natural, and the radicals formed were studied by electron spin resonance(ESR) coupled with the aid of systematic computer simulations. On the basis of the findings from a series of such studies, we were able to develop several novel biomedical application works in the field of biomaterial engineering. In this contribution, our novel application works in drug engineering on plasma-irradiated organic polymers will be presented, which include (1) preparations of multilayered tablet applicable for drug delivery system(DDS)of sustained- and delayed-release, (2) fabrication of functionalized composite powders derived from plasma-irradiation onto powdered polymers followed by mechanical applications in the presence of powdered drugs under anaerobic conditions,(3) preparation of biocompatible biomedical polymer surface useful for cathetal, as well as overviews of ESR studies on plasma-induced radicals of a variety of organic polymers.