In this study, self-assembled tea catechin/gelatin nanoparticles were prepared by directly mixing the catechins and gelatin solutions. The mean particle sizes were almost less than 200 nm, and the zeta potential values were negatively charged. FT-IR spectral analysis indicated that hydrogen bonding between aliphatic and aromatic hydroxyl groups, respectively, on gelatin and catechins is responsible for the self-assembly of nanoparticles. Free radical (DPPH* and ABTS*(+)) scavenging assays showed that tea catechins could be protected by the nanoparticles and that the antioxidant activity of tea catechins was almost retained after three weeks of storage. The tea catechin/gelatin nanoparticles exhibited 28-41% inhibition to trypsin against the degradation of gelatin. This result suggested that the tea catechin/gelatin nanoparticles might be a useful antioxidant carrier because catechins and gelatin were, respectively, protected from oxidation and enzymatic digestion.