A novel mixed matrix membrane (MMM), ZSM5-polybenzoxzine, has been successfully fabricated MMM combines the advantages of both matrix and filler to improve the performance of gas separation. The SEM micrographs revealed good interfacial adhesion between the polybenzoxazine and ZSM-5 particles since no micron size void was observed. The XRD patterns showed no changes in the crystal structure of the ZSM-5 after mixing with the polymer matrix. CO₂ and CH₄ permeability were determined by using the single gas measurements. The CO₂ and CH₄ permeability of MMM was decreased with increasing zeolite content, while the CO₂ CH₄ selectivity was also increased with an increase in the zeolite loading.