Effects of various types and amounts of plasticizer on the moisture sorption and mechanical properties of gelatin-chitosan composite films were investigated. The films were plasticized with glycerol, polyethylene glycol 400 (PEG 400), polyethylene glycol 800 (PEG 800), and sorbitol, respectively. With increasig the amount of plasticizers in the composite films plasticized with the fromer three plastizers, the equilibrium moisture sorption ratio increases. For the last one, however, it decreases with increasing the plastizers content. Increasing the plasticizer content decreases the tension strength and increases the elongation at break of the samples, and the type and amount of the plasticizers affect the mechanical properties of the composite films. PEG 400 is the most effective plasticizer in the plastizers studied.