The influence of metal-polymer interaction on dielectric relaxation properties of polyurethane (PU), prepared from poly(oxypropylene)diol and hexamethylendiisocyanate, was investigated by means of dielectric relaxation spectroscopy in the frequency domain on the dependence of the thickness of the PU layer and electrode material (gold and steel). Strong electrostatic part of an adhesion interaction between steel substrate and PU results in changes of the alpha-, beta-, gamma- and Maxwell-Wagner-Sillars relaxation of the PU, as compared to a gold substrate. The effect of the metal-polymer double layer results in the complication of the cooperative and local motions in the polymer. The influence of metal-polymer interaction on the relaxation parameters becomes pronounced at a thickness of less than 60 mu m for the steel substrate. For the gold substrate the relaxation characteristics hardly depend on the thickness.