The optical activity of chitosan films in the forms of polysalt (chitosan acetate) and polybase was studied. The specific optical rotation [α] of all our films was negative. The absolute values of [α] of polybasic chitosan films was by an order of magnitude higher than that for polysalt films. A dependence of [α] on the orientation angle of the sample relative to the direction of the polarization vector of the incident light beam in the plane perpendicular to this beam was established. Specific optical rotation indicatrices of the chitosan films of both chemical forms were plotted.