Seventeen rice promising mutant lines had been induced from Giza 176 (91ines) and Giza 171 (8 lines) rice varieties by Gamma irradiation treatment with 10, 20, 30, 40 and 50 kr using ⁶⁰Co. Sources were selected from previous study and examined for some agronomic, disease resistant and grain yield traits in the M₈ and M₉ generations during 2000 and 2001 rice growing seasons at the farm of Rice Research and Training Center, Sakha, Kafr El-Sheikh, Egypt. The results indicated that most of Giza 176 mutants (G. 176-Mut. 2, 3, 6 and 9) showed superiority over their parent for earliness, semi-dwarfness, leaf and panicles blast and false smut resistance. Higher productive tillering ability and high yielding (46, 48, 43 and 44 g / plant), respectively, comparing with their control Giza 176 (35 g/plant) in M9 generation.  Furthermore, both G. 176 Mut. 4 and Mut. 5 headed (26 and 19 days) earlier than its parent Giza 176 (Late variety), respectively, but lower in their yield.  Regarding Giza 171 mutants some of them exhibited describle traits. For short stature Giza 171 mutant 4,5 and 6 were shorter than their control parent about (27 cm), as well as Giza 171 M 7 for number of panicles/plant and Giza 171 Mut. 6 and 7 for grain yield/plant.  On the other hand, Giza 176 Mut. 1, 2, 3, 4 and 5 were earlier than their parents approximately 20 days. In addition, genetic studies revealed that low genetic variance together with low to moderate estimates of broad sense heritability and low expected genetic advance were recorded for all the studied traits with some exceptions. In both G. 176 and G. 171 mutants suggesting that, these promising mutants, may be bred true for these studied traits and therefore can be used as a new rice varieties or as a donors in rice breeding program.      As for as diseases resistance is concerned, data indicated that most of Giza 176-Mut.1, 2, 4, 6 and 8 were resistance to blast (leaf and panicles) and false smut diseases, while Mut. 5 and 9 were resistant to blast only. Also, Giza 171-mutants 2, 3 and 4 were resistance to blast (leaf and panicles) and false smut diseases