Aleurone, the principal nourishing layer in the rice grain, consists of one to several layers of uniform, highly differentiated cells (Beteke et al 1997). In cooking, the starchy components in the caryopsis expand both laterally and vertically. This study was undertaken to determine the effect of cooking on aleurone in the rice caryopsis. Local varieties used in this study were long-, medium-, and short-grain types. Rice grains were dehusked manually and cooked in a domestic cooker with excess water, with and without aleurone. To attain a caryopsis without aleurone, the aleurone layer was manually removed. For the measurement, an average of 100 grains was used.