This study was caried out in 2004 and 2005 rice growing seasons in the research farm of Rice Research & Training Center, Sakha, Egypt, to investigate the genetical behaviour of some root characters as a key for drought tolerance in rice. These characters were, root length, root thikness, root dry weight, root volume, and root/shoot ratio.The brogenies of three rice crocess namely; Saka 101/ IET 1444, Giza 178/Moroboreken and Giza 182/ RD9 were utilized in this study. The results showed that additive genetic variance plays an importent rolre in the inheritance of most of studied characters except for root dry weight and root/shoot ratio where the dominance one was found to be more imbortant. Heritability values in  braod sense were high and ranged between 87% (for root dry weight) and 93% (for root length) Meanwhile, narrow sense heritability estimates ranged between low (43%) and intermediate (56%) for root/shoot ratio and root length chracters, respectively.These results indicated that all studied characters are affected by the invironmental factors an in turen selection for improving such characters must be prctecied in advanced generation.