Porous barium titanate ceramics were produced by solid state synthesis. Stoichiometric amounts of high-purity powders containing 0.18 wt.% of La2O3 were mixed by ball-milling. The resultant mixtures were dried, sieved and were cold pressed into green samples then sintered at 1200-1500 degrees C for 6h. in air to form the perovskite phase. The porosity of the sintered bars were measured by Archimedes method. The obtained ceramics were characterized by SEM. The average grain size values and microstructural features were determined for four different compositions. The electrical conductivity values were measured under humid environment and transformed into humidity sensitivity values. Effects of porosity and working temperatures on porous barium titanate ceramics were investigated and results were evaluated in terms of microstructure.