A study was carried out to investigate the effects of two different types of whitening machines (friction and abrasive) and five different whitening times (30,45,60.75 and 90 sec) on whitening characteristics of short grain rice varieties (Giza177,Giza,178, Sakhal01 and Salchal02) and long grain varieties (Yasmin and Giza182). The evaluation basis included total and head rice yield, whiteness degree of milled rice, nutrition constituents, and electric power consumption. The results showed that, for all studied varieties, the total and head rice yields decreased with the increase of whitening time and they were higher for the abrasive type whitening machine in comparison with the friction type. Meanwhile, prolonged continuous whitening (over 60sec) slightly increased the whiteness degree of milled rice but brought about a drastic reduction in head rice yield for both types of whitening machines. Also, as whitening progressed from low to high degree of whiteness, the levels of protein, lipids, ash, and minerals decreased, while the level of starch increased. On the other hands, the friction type whitening machine recorded higher power consumption in comparison with the abrasive type. However, the power consumption increased with the increase of whitening time for the abrasive type whitening machine, while it decreased for the friction type.