A pot experiment was conducted in green-house of Soil and Water Research Department, NuclearResearchCenter, Abou-Zaabal, Egypt in winter 2016. Nitrogen fertilization management and irrigation water regime were as field practices were followed to improve sugar beet production under salinity stress condition.  Sugar beet plants were irrigated with 8 and 16 dS m^-1 saline water at 100%, 80% and 60% water regimes. Plants were fertilized with 100%, 80% and 50% of fertilizer-N recommended rates. Shoot dry weight was not significantly affected by experimental factors while root dry weight significantly but negatively affected by reduction in water quantities and raise of water salinity. On the other hand, dry weight of root of plants treated with N50 was superior over other N rats especially under W80 and W60 water regimes. Nitrogen uptake by shoot and roots was variably significantly affected by water and N fertilizer regimes under different water salinity levels. Based on mean averages of water and nitrogen treatments, W100, N80 and N100 interacted with salinity levels were the best treatments. Generally, N uptake was negatively affected by shortage in water requirement (regime). The highest values of N uptake by shoots of plants irrigated with 8 and 16 dS m^-1 salinity levels were recorded with application of 50% N recommended rate. N80 and N100 interacted with salinity levels resulted in the best N uptake by root under W100, W80 and W60, respectively. Nitrogen derived from fertilizer (Ndff) by shoot tended to be reduced with irrigation water shortage up to W60 (water scarce). On the other hand, in most cases, Ndff values were increased with irrigation water salinity levels. It means that sugar beet as salinity tolerant plant acted well and able to gain more nitrogen from chemical fertilizer. More Ndff by shoot was gained when plants fertilized with either N80 or N50 rates. Ndff by root was negatively affected by shortage of water requirement and declined with increasing water salinity but enhanced with low rate of chemical fertilizer added especially at W100 regime. Interaction of salinity and nitrogen rates (S x N) resulted in the increase of %NUE with S8 and S16 salinity levels comparing to fresh water (FW) treatment. This was true, but in low extent, with W80 and W60 water regimes. The highest %NUE by root was recorded with N50 interacted with FW under W100 regime. It means that low N rates meet the plant demand without risk on production and achieved the most benefits from the added doses.