The mechanical properties of films prepared from mixed acetic acid aqueous solutions of chitosan (M-w = 400,000; M-w/M-n = 3.8) and poly(ethylene oxide) (PEO) (viscosity average molecular weight of 200,000 or 600,000) were determined. A chitosan:PEO weight ratio of 10:2 improved the mechanical properties compared with pure chitosan films. The improvement of the mechanical properties correlated with a small reduction of the correlation length measured by small-angle neutron scattering (SANS).