A novel method for predicting the porosity dependence of ultrasonic and elastic properties of isotropic ceramics after sintering based on the properties of green or partially sintered compacts has been proposed. The method is based on the observation that the ratio of ultrasonic shear wave to longitudinal wave velocity is a function of porosity only and varies linearly with the longitudinal wave velocity. It is also shown that the predicted trend of variation of Poisson's ratio with porosity agrees with the predictions of the Mori-Tanaka mean field approach. The method can be used as a quality control tool during the preparation of ceramic materials.