Amorphous nylon 6 film iodinated before forming with an aqueous Solution of 1.0N iodine-potassium iodide (I-2/KI) was deiodinated by dipping in water/ethylene glycol (EG) solutions of sodium thiosulfate with various EG contents and temperatures, washed with water, and dried at ambient condition. Structural variation through deiodination and the effects of the deiodination conditions were investigated by X-ray diffractometry and differential scanning calorimetry. The degree of swelling of the films immediately after deiodination and the time required to complete the deiodination were generally increased and decreased, respectively, with increasing temperature and EG content. The amorphous iodinated film was crystallized through deiodination. The alpha-crystal formation became easier with increasing temperature and EG content in the Solution. The crystallinity of the films was higher after drying than before drying, suggesting that the drying induced further crystallization without any significant conversion of crystal type. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 1141-1145, 2009