Large area,  about 200,000 feddan, of salt affected soil at north Nile Delta has been put under cultivation since 1970.This area suffers from water supplying for irrigation because,  these area lie at the end of the canals.  Filed experiment was conducted by using drainage water (EC=3.8 dSm^-1, SAR=3.69), to irrigate sugar beet crop  grown on a clay saline soil (ECe=10.1dSm^-1). The aim of the study was, to investigate effects of water irrigation salinity and the irrigation intervals on growth, yield and quality of sugar beet crop, cultivated on saline clay soil at El-Hamoul, Kafer El-Sheikh governorate. The experiment comprised planting sugar beet with three irrigation intervals as main plot, namely; two weeks (I₁), three weeks (I₂) and four weeks (I₃). Three irrigation water salinities as sub plot; S₁ fresh water (0.5dSm^-1), S₂ mixed water (1.8dSm^-1) and S₃ drainage water (3.8dSm^-1). Sugar beet (Beta vulgaris L) seeds were planted by hand and irrigated with fresh water (0.5 dSm^-1) until sugar beet plants had 6- 8 leaves. Then the plots received different irrigation water with different intervals according to treatments. Results showed that irrigation every 2 weeks with fresh water (treatment I₁ S₁) produced the highest sugar beet yield and the highest sugar percent, 27.03 ton/fed. and 18.2%, respectively. While irrigation every 4 weeks with drainage water (I₃ S₃) produced the lowest yield,18.4 ton/fed., and the lowest sugar percent, 13.1 %. Irrigation with drainage water (S₃) significantly reduced the beet root yield by about 21% relative to irrigation with fresh water (S₁). Also water salinity 3.8dSm^-1 significantly reduced beet root yield quality. The lowest beet root quality was obtained with the drainage water.  Increasing irrigation intervals from 2weeks up to 4 weeks, significantly decreased the root yield of sugar beet .The sugar percent of sugar beet, also, slightly decreased but not significantly, with increasing the irrigation interval .It could be concluded that irrigation at short intervals could compensate, partially, the hazard effect of the water salinity on the crop yield. Under the condition of the present study ,  irrigation every 2 weeks with water salinity up to 3.8 dSm^-1,had an acceptable sugar beet root yield (22.1 ton roots/fed) of satisfactory quality(2.89 ton sugar/fed). The productivity of irrigation water (PIW) for both of root and sugar yields decreased with increasing salinity of irrigation water, but this decrease was lower for sugar yield than root yield. Increasing the irrigation intervals from 2 weeks to 4 weaks increased the (PIW) of root yield from 7, 28 to 8.8 kg/m^-3, and that of the sugar yield from 1.12 to 1.51 kg/m^-3. On the light of this study, it could be recommend the possibility of irrigating  sugar beet with drainage water (S₃), at 2 or 3 weeks intervals, to obtain economical yield with satisfactory quality.