The electrical conductivity of yttria stabilized zirconia (YSZ), prepared by precipitation from aqueous solutions of inorganic precursors, was measured as a function of composition, temperature of annealing prior to conductivity measurements (900 degrees C-1700 degrees C), and temperature of measurement (500 degrees C-900 degrees C). A comparison is made with the more dense YSZ prepared by the dry powder method : the conductivites are very near when the same high annealing temperatures are applied. The considerable increase in the conductivity attained by raising the annealing temperature of the precipitated material is suggested to be largely due to an increase in density. The effect of other factors is considered.