The structural characterization and transport properties of blends of a commercial high molecular weight poly(epsilon-caprolactone) with different amounts of a montmorillonite-poly(epsilon-caprolactone) nanocomposite containing 30 wt % clay were studied. Two different vapors were used for the sorption and diffusion analysis-water as a hydrophilic permeant and dichloromethane as anorganic permeant-in the range of vapor activity between 0.2 and 0.8. The blends showed improved mechanical properties in terms of flexibility and drawability as compared with the starting nanocomposites. The permeability (P), calculated as the product of the sorption (S) and the zero-concentration diffusion coefficient (D-0), showed a strong dependence on the clay content in the blends. It greatly decreased on increasing the montmorillonite content for both vapors. This behavior was largely dominated by the diffusion parameters.