Dielectric studies have been carried out on semi-crystalline poly(ether-ether-ketone) at temperatures from 100 to 300°C and at frequencies between 20 Hz and 10 kHz. A relaxation is seen in the isochronal curves and in the Cole-Cole plots, which is attributed to a Maxwell-Wagner-Sillars polarization taking place at the interface between the crystalline inclusions and the amorphous matrix. The intensity of this relaxation is presented in relation to the morphology of the crystalline part which is known to depend on annealing conditions.