The polymer electrolytes based on chitosan and ammonium chloride were prepared by solution casting technique and the properties were studied. The addition of ammonium chloride results in: (1) the enhancement of the amorphous nature of the polymer electrolytes; (2) the shift of the absorption bands of amino group at 1566 cm(-1) and the carbonyl group at 1640 cm(-1) towards lower wave number, and the appearance of a new absorption band at 1759 cm(-1); (3) a decrease of the glass transition temperature. The 20 wt% ammonium chloride doped polymer electrolyte has the best room temperature electric property, the lowest activation energy and the highest ionic conductivity. Placing the as-prepared polymer electrolyte in a dryer is adverse for the sample's moisture content, and results in higher activation energy and lower ionic conductivity. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48:260-266, 2010