Two field experiments were cared out in El-Sirw Agricultural Research station ,at Damitta Governorate in 2005 and 2006 seasons , to study the effect of four irrigation treatments i.e. continuous flooding , irrigation withholding for 10 days at 25 day after transplanting (DAT),irrigation withholding for 10 day at 25 and 45 DAT and irrigation withholding for 10 day at 25,45 and 65 DAT and potassium as a foliar application i.e. one spray (at 25 DAT),tow sprays (one at 25 and one at 45 DAT) and three sprays (one at 25 ,one at 45 and one at 65 DAT) on growth ,yield, yield components of three rice varieties i.e. Giza 178 , Sakha101 and Sakha103. Spilt-split plot design with four replications was used . The optianed results showed that increasing water deficit (irrigation withholding at 25,45 and 65 DAT) decreased number of panicle /m2, panicle grain weight, 1000-grain weight, grain yield per feddan, straw yield per feddan, increased compared to all other irrigation treatments in both seasons. Data recorded indicated that rice varieties significantly differed in all studied characters in both seasons . Variety Giza 178 exceeded Sakha 101and Sakha 103 in number of panicle /m2, and grain yield per feddan in seasons. Results exhibited that increasing number of potassium spraying increased values of all previously mentioned studied traits. The high at grain yield was recorded with plants received three potassium spraying in both seasons. At the highest water deficit (irrigation withholding for 10 day at 25, 45 and 65 DAT),verity Giza 178 supposed in grain yield per Fadden compared to other used variety in both seasons. At the highest water deficit application potassium with three sprayings increased values of all studied characters. The highest grain yield was obtained when variety Giza 178 received three potassium sprayings compared to other variety under study in both seasons. Fertilized variety Giza 178 by potassium at the three sprayings under the highest water deficit increased grain yield per Feddan in both seasons .