Two field experiments were conducted at Sedment El-Gabal location, Beni-Sweif Governorate during 2007/2009 seasons to study the response of sugar beet yield and some of its attributes under sprinkle irrigation to different N rates; 100, 120, 140 and 160 kg N/fed and its time of application viz., split application in two equal doses, at 4- and at 8-leaf stage, or in three equal doses,1/3 at 4- leaf stage, 1/3 at 8-leaf stage and 1/3 three weeks later, or dividing the rate into 4 equal doses and added 1/4 at 4- leaf stages, 1/4 at 8- leaf stage, 1/4 three weeks later and 1/4 three weeks after the last. A split plot design with four replications was used, where N rates were allocated in the main plots and time of N application was distributed at random in the subplots. Results obtained from this study revealed that increasing N rates from 100 up to 160 kg N/fed significantly increased root weight by 16.52% and 24.77%, number of plants at harvest by 4.05 and 2.89 thousand plants/fed and root yield by 7.22 and 8.34 tons/fed in the first and second seasons, respectively. Excessive N rate lowered beet quality in terms of sucrose content, juice purity and extractable sucrose. Extractable sugar yield increased by increasing N rates from 100 to 120 Kg/fed.  Such increase amounted to 29.08 % in the first season and 31.97 % in the second one. Additional increasing in nitrogen rate beyond 120 kg N/fed had no significant effect on sugar yield.  Splitting N rate into 4 equal doses significantly increased weight of individual root and number of plants/fed at harvest. Late N application in favour of N splitted into 4 doses gave the highest root yield/fed. On the other hand, early application and splitting N in two equal doses at 4-and at 8-leaf stage improved beet quality traits in terms of sucrose %, purity % and extractable sucrose %. Splitting 160 kg N/fed into 4 equal doses gave the highest root yield, while splitting 120 kg N/fed into 4 equal doses was recommended for high sugar yield/fed.