gamma -Irradiation was used to prepare homogenous nanocrystalline composites of CdS/polyacrylonitrile with 19.4 wt% cadmium sulfide at room temperature. Powder X-ray diffraction and infrared spectroscopy were used to characterize the products. The morphology of the product was determined by transmission electron microscopy. The photoluminescence property of as-prepared CdS/polyacrylonitrile nanocomposites was also studied.