An optical fiber cable having a polymeric component, in particular a buffer tube, suitable for both terrestrial and undersea uses. The polymeric material forming the component has a copolymer of propylene with a C.sub.4-C.sub.8 .alpha.-olefin and preferably a nucleating agent disbursed therein. The obtained component shows improved dimensional stability, which guarantees its non-deformability, and high transparency and can be extruded at lower extrusion temperatures.