Doping effects on the dielectric properties of low temperature sintered lead-based ceramics were studied. PZT-based and 0.25Pb(Ni1/3Nb2/3)O-3-0.75Pb(Zr0.52Ti0.48)O-3 (PNN-PZT)-based ceramics, modified with Bi2O3, Fe2O3, CuO, MnO2, and Ba(Cu0.5W0.5)O-3, were prepared by conventional mixed-oxide technique, with sintering temperature at 850-950 degrees C. Microstructural and compositional analyses of these low temperature sintered lead-based ceramics were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM). In this paper, we successfully show that these additives were helpful in both lowering the sintering temperature and improving the dielectric properties. The preferred sintering condition is also reported. The following dielectric properties were obtained: epsilon(33)(T)/epsilon(0) = 900, tan delta < 10 X 10(-3), rho = 7.5 g/cm(3) for the PZT-based family; epsilon(33)(T)/epsilon(0) = 4000, tan delta = 35 X 10(-4), rho = 7.82 g/cm(3) for the (PNN-PZT)-based family.