Nanocomposite materials were obtained from a colloidal suspension of high aspect ratio P chitin whiskers as the reinforcing phase and poly(caprolactone) as the matrix. The chitin whiskers, prepared by acid hydrolysis of Riftia tubes, consisted of slender parallelepiped rods with an aspect ratio close to 120. A procedure was optimized to prepare a latex of poly(caprolactone). After mixing and stirring the two aqueous suspensions, solid films were obtained by either freeze-drying and hot-pressing or casting and evaporating the preparations. An amorphous poly(styrene-co-butyl acrylate) latex was also used as a model matrix. The thermal and mechanical properties of the resulting films were evaluated, The reinforcing effect of chitin whiskers is discussed on the basis of different types of mechanical models, and it is concluded that these whiskers form a rigid network assumed to be governed by a percolation mechanism. The formation of this network allows the thermal stabilization of the material for temperatures higher than the melting temperature of the poly(caprolactone).