Two field trials were conducted in 1998/99 and 1999/2000 seasons in Kafr El-Sheikh governorate to study the effect of various nitrogen rates i.e.60, 80, 100, 120, 140, and 160% of the recommended rate (RR) (RR=75kg N/fed) on root quality, technological parameters and yield of sugar beet. Analysis of variance revealed that: Increasing N dressing up to 90 kg N/ fed (20% over RR) exhibited the highest root quality, technological parameters, root and sugar yield ton / fed and minimized sugar lost to molasses. On the other hand, further N dressing decreased markedly the most studied traits. Nitrogen dressing enhanced the content of N, P, K and Na, where a significant improvement in the concentration of those elements in samples of beet leaves and roots aged 90 and 150 days from sowing. Accumulation of 16 amino-acids % tended to increase in beet root at harvest as nitrogen rate increased. Glutamic acid was in an abnormally high concentration under various nitrogen rates followed by Aspartic acid and the remaining acids were found in relatively low concentration. It could be recommended, under the condition of this work, increasing N dressing up to 90 kg /fed (20% over RR) to maximize root and sugar yield