Barium titanate (BaTiO3, BT)-bismuth magnesium titanium oxide [Bi(Mg0.5Ti0.5)O-3, BMT] system ceramics were prepared in an ambient atmosphere in order to increase the Curie temperature (T-c) of BT above 132 degrees C. A single perovskite phase was observed for BT-BMT ceramics with BMT compositions less than 50 mol %, and their relative densities were greater than 94%. Synchrotron measured x-ray diffraction patterns revealed that all the cations in the ceramics were homogeneously distributed. The temperature dependence of the dielectric properties revealed that the BT-BMT system ceramics exhibited relaxorlike characteristics with a dielectric maximum temperature as high as 360 degrees C for the 0.5BT-0.5BMT ceramic. The apparent piezoelectric constant (d*) was 60 pC/N for the 0.4BT-0.6BMT ceramic. Based upon these results, the BT-BMT system shows potential as a new type of lead-free material for high T-c piezoelectric applications.