Two filed experiments were conducted during 2012 and 2013 seasons at the Experimental Farm of Rice Research and TraIningCenter, Sakha, KafrEl-Sheikh, Egypt. The experiment aimed to study the effect of irrigation intervals and potassium splitting on Egyptian hybrid one (EHR1) rice cultivar. The study was performed in strip plot design with four replications. The irrigation intervals; irrigation every 3, 6 and 9 days were placed in the horizontal plots, while the potassium splitting treatments, namely; K₁: All basal (B), K₂: ½ B + ½ mid tillering (MT), K₃: ⅓ B + ⅓ MT + ⅓ panicle initiation (PI) and  K₄: ¼ B + ¼ MT + ¼ PI + ¼ booting stage (BT) were distributed in the vertical plots.  Some growth characteristics, chlorophyll content, leaf area index and dry matter production m^-2 were assessed at heading stage. Yield and yield attributes were measured at harvest .Some water relations were also estimated during current study.                 The resulted indicated that irrigation intervals had significant effect on all studied traits in both seasons of study. The prolonging irrigation intervals up to 9 days significantly reduced rice growth, yield attributing characteristics, rice grain and straw yields as well as harvest index. The irrigation intervals every 3 and 6 days were placed at the same level of significant in both seasons of study regarding the rice growth, yield contributes, grain yield and harvest index. The irrigation interval every 3days treatment consumed the highest amount of total applied water (13492.9 and 13609.8m^/3 ha^-1) with the lowest values of water use efficiency (0.811 and 0.814 kg/m³) during first and second  seasons, respectively. The irrigation interval of 9 days gave the highest values of yield reduction (18.01 and 19.22%), water save (20.23 and 21.50 %) and medium value of water use efficiency (0.833 and 0.838 kgm^-3) in 2012 and 2013 seasons, respectively. The irrigation interval of 6 days had the highest values of water use efficiency (0.894 and 0.899 kgm^-3) with mild yield reduction of (1.65 and 1.81%) and its water save was amounted to be 10.76 and 11.03% in the first and second seasons, respectively.                 The potassium split treatments significantly improved rice growth, yield contributes, rice grain and straw yields as well as harvest index comparing to one dose application as basal. The potassium splitting into four equal  doses, ¼ B + ¼ MT + ¼ PI + ¼ BT significantly surpassed the rest of treatments whereas; it gave the highest values of all measured traits, while potassium application as one dose gave the lowest values of all measured traits under current study in both seasons. The potassium split into four equal doses gave the highest values of water use efficiency (0.897 and 0.905kgm^-3) in both seasons of study. Generally,  both of potassium splitting into three equal doses, ⅓ B + ⅓ MT + ⅓ panicle initiation (PI) and potassium splits into equal four doses were placed in the same group regarding superiority effect on dry matter gm^-2, number of paniclesm^-2, total number of grainspanicle^-1, number of filled grainspanicle^-1, 1000-grain weight, grain yield, straw yield and harvest index as well as water productivity. The interaction between irrigation intervals and potassium treatments had significant effect on chlorophyll content, leaf area index, dry matter production m^-2(only in 2012 season), plant height cm, and number of paniclesm^-2, number of total grains panicle^-1, number of filled grains panicle^-1, 1000-grain weight, grain yield, straw yield and harvest index in both seasons of study. Generally, the results of interaction proved that irrigation interval of 6 days could be recommended for rice cultivation with potassium splitting in four equal doses to save water and high water use efficiency. It could be concluded that the potassium splits in to four equal doses including PI and booting stage could be recommended under 6 days irrigation interval to ensure  high grain yield and water productivities. Potassium splitting applications at critical different rice growth stages confirms an adequate amount of potassium supply at the correct time mitigating the adverse effect of water stress and produced considerably yield.