A series of La1-xSrxAlO3-x/2 phases were prepared from x = 0.00 to 0.35 at 1550 degrees C in air. Rhombohedral symmetry was observed for values of x up to 0.27, but the La0.65Sr0.35AlO2.725 sample appears to be cubic. Dieletric measurements on sintered pellets show the dielectric constant decreasing from about 24 to 19 with Sr substitution, whereas dielectric loss increases from 10(-4) to 2.5 X 10(-3).