Two field experiments were conducted at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt during 2011 and 2012 seasons to investigate the effect of irrigation intervals, organic and mineral fertilization on the growth, grain yield, technological characteristics of grains and some water relations of two hybrid rice genotypes. A split split–plot design with three replicates was used. The main plots were devoted to four irrigation treatments namely, continuous flooding (CF), irrigation every 6 days (6-day), irrigation every 8 days (8-day), irrigation every 10 days (10-day). The sub plots were occupied by two hybrid rice genotypes namely; Egyptian hybrid rice one (EHR1) and SK2046H hybrid rice (SK2046H). However, the sub-sub plots were consisted of organic and mineral fertilization as follows : (T1) zero fertilizer (control), (T2) 160 kg N + 40 kg P2O5 + 60 kg K2O /ha (recommended level), (T3) compost (5 t/ha), (T4) 40 kg N + 10 kg P2O5 +15 kg K2O/ha + compost (5 t/ha), (T5) 80 kg N + 20 kg P2O5 + 30 kg K2O /ha + compost (5 t/ha), (T6) 120 kg N + 30 kg P2O5 + 45 kg K2O/ha + compost (5 t/ha) and (T7) 160 kg N + 40 kg P2O5 + 60 kg K2O /ha + compost (5 t/ha). The results obtained could be summarized as follows: The data indicated that CF followed by 6-day recorded the highest values of grain yield and its components (number of panicles/m2, panicle length, number of total grains/ panicle, sink capacity, panicle density, 1000–grain weight, panicle weight, grain, straw and biological yields/ha as well as harvest index), grain quality (hulling, milling and head rice percentages) and grain chemical analysis (N, P, K and protein percentage). On the other hand, irrigation every 10 days recorded the highest values of days to heading, unfilled grains and broken rice percentages in both seasons. EHR1 genotype recorded the highest values of grain yield, grain yield components, grain quality and chemical analysis of grains. However, SK2046H genotype recorded the highest values of panicle length and unfilled grains and broken rice percentages in both seasons. Fertilization treatments had a marked effect on characteristics studied in favor of fertilization treatments of T7, T2 and T6 which gave the highest values of grain yield, grain yield components, grain quality and chemical analysis of grains. However, unfertilized plants (T1) gave the lowest values of most characteristics studied. It can be concluded that it is possible using the irrigation system every 6 days with the application of mineral fertilizer of 120 kg N + 30 kg P2O5 + 45 kg K2O /ha + organic fertilizer of compost (5 t/ha) for saving some amounts of irrigation water by about 10 % as well as mineral fertilizer of NPK by about 25 % with insignificant and minimum reduction in grain productivity of hybrid rice genotypes.