A range of different pore size zirconias have been prepared by varying the thermal treatment following a sol-gel preparation. Increasing the temperature of calcination increased the pore size, decreased the surface area, decreased the microporosity and decreased the pore volume. Inclusion of sodium chloride in the zirconia matrix during calcination at the melting point of the sodium chloride opened the necks of ’ink bottle’ shaped pores and transformed them into cylindrical shaped pores. The salt had the effect of lowering the rate of decrease in pore volume and surface area as the calcination temperature increased while the pore size increased slightly compared with that of a zirconia calcined without the salt under otherwise exactly the same conditions.