Gamma-irradiation was used to produce freestanding, sterilized, cross-linked caseinate films and gels. Mechanical properties of gels and films and water vapor permeability of dried films were determined. Irradiated films were significantly ( p less than or equal to0.05) more resistant to puncture and moisture. Also, gels were formed when protein solutions received radiation doses greater than or equal to16 kGy. The addition of CaCl2 in the solution containing proteins, glycerol, and carboxymethylcellulose (base formulation) increased significantly the puncture strength for the films atirradiation doses greater than or equal to16 kGy. Sorbitol had the greatest plasticizing effect andsignificantly ( p less than or equal to0.05) increased distance to puncture, while mannitoldecreased distance to puncture. Size-exclusion chromatography performed on the irradiated solutions of the base formulation showed that gamma-irradiation increased the molecular weight of calcium caseinate by 100 times; the molecular weight was greater than or equal to2x10(3) kDa. Films produced with base formulation were alsoimmersed in flasks containing 100mL of boiling water during 30 min forinsolubility measurements. Results showed that the proportion of the insolublefraction increased with the irradiationdose. Seventy percent of the irradiated films (32 kGy) remained insoluble after immersion in water at 100degreesC, 30 min and 20degreesC, 24 h. Water vapor permeability (WVP) of the base formulation films was reduced from 3.99+/-0.23 to 2.57+/-0.63 g.mm/m(2) .d.mmHg after irradiationtreatment. Microbial resistance of cross-linked films (base formulation)showed that 36% of N from calcium caseinate films was converted to soluble N after 60 d in presence of Pseudomonas aeruginosa.