In this article, poly(ester ether) multiblock copolymer/organomontmorillonite hybrid nanocomposites were prepared via an intercalation polymerization process. The resulting hybrid nanocomposites were characterized by X-ray diffraction, differential scanning calorimeter, and transmission electron microscopy. The results proved that the organomontmorillonite (organo-MMT) could be exfoliated into similar to 50-nm thickness and dispersed in the poly(ester ether) multiblock copolymer (TPEE) matrix during the intercalation polymerization process. TPEE/organo-MMT nanocomposites showed excellent mechanical properties compared with the unfilled TPEE. When the organo-MMT content was about 3-5 wt %, MMT could enhance the strength, modulus, and hardness of TPEE without sacrificing its elongation at break.