Nanocomposites of organophilic montmorillonite clay (OMMT) and polyepichlorohydrin (PECH) were intercalated by a solvent-casting method using dichloromethane as a solvent. The intercalation of PECH segments in the interlayers of the clay was confirmed by X-ray diffraction, and the intercalation spacing was calculated. The increase in the onset temperature of the thermal degradation indicated the enhancement of thermal stability of PECH due to intercalation. Rheological properties of the PECH/OMMT nanocomposites were investigated using a rotational rheometer in a steady shear mode. The steady shear viscosity increased with the clay loading, and the shear thinning viscosity data were fitted well with the Carreau model. From the normalized shear viscosity analysis, a critical shear rate that is a crossover from a Newtonian plateau to a shear thinning region was found to approximately equal the inverse of the characteristic time of the nanocomposites.