The temperature dependence of the pyroelectric and dielectric response as a function of a selected DC electric bias field has been investigated for several different compositions of the PMN-based ceramic. The selected DC electric bias field which gives the maximum pyroelectric coefficient was determined by a study of the pyroelectric coefficient, measured by the Byer-Roundy method, at several poling fields. The large values of the figure of merit (p/(K) 1/2) found in these PMN-based compositions, suggest this material as a promising candidate for pyroelectric point detectors since this figure of merit is comparable to the materials most widely used, TGS and LiTaO3, for point detectors.