The purpose of this study was to investigate the reinforcement effect of the cuttlebone particle on the mechanical properties of natural rubber (NR) vulcanizates. The extraction of organic compound from the cuttlebone was prepared demineralization and deproteinization methods. The obtained chitin had been characterized by Fourier Transform Infrared Spectroscopy (FTIR). The mechanical and thermal properties of NR composite materials were investigated. The reinforcement effect of cuttlebone particle in NR composite was comparable with that of commercial CaCO3 as a reference. After thermal aging, the tensile properties of composite material were decreased. The presence of organic component was speculated to give a good interaction effect of cuttlebone particles to NR as revealed by Scanning Electron Microscopy (SEM).