Rubber materials are composed of various compounds such as cross-linked polymers, additives, and fillers. It is difficult to analyze such materials in their normal state because of lack of volatility and solubility, and time-consuming and cumbersome sample pretreatment is inevitably required depending on the type of analytical methods. However, pyrolysis (Py) of rubber materials under inert gas decomposes them into many individual fragments, which can be separated and identified by GC/MS. Thus, Py-GC/MS can directly analyze materials without any sample pretreatment and is quite useful for the characterization of polymer and copolymer materials including additives and fillers. This article reviews Py-GCMS analysis of rubber materials, such as determination of rubber types, quantification of composition ratio of copolymers, and qualitative and quantitative analysis of compounded additives.