In this study, the structure and properties of an organic-inorganic composite fiber, prepared from nylon 6 doped with fine particles of silver iodide (AgI), were examined. The preparation of the composite fiber involved the complexation of nylon 6 with polyiodide ions such as I3. and I5. by immersion in an iodine-potassium iodide(I2-KI) aqueous solution, followed by reaction in an AgNO3 aqueous solution, resulting in the in-situ precipitation of Beta-AgI fine particles within the nylon 6 fiber. AgI was formed as anisotropic particles, and displayed crystallite orientation in the oriented nylon 6 fiber. This is attributed to the orientation of polyiodide ions, as the precursor of AgI, in the orientated nylon 6 chain. The composite exhibited conductivity of approximately 10.5 ohm-1 cm-1.