The present study was conducted at a private  Farm, Kalabsho, Belqas Center, Dakahlia Governorate during the two successive seasons of 2014/2015 and 2015/2016.  This investigation was layout to find the effect of Cultivars (Gloria and Diamond), phosphorus (0, 12, 24, 36, 48 kg P₂O₅ fed ^-1 as a mono-super phosphate) and boron (0 , 0.750 and 1.125 kg Borax fed^-1 ) and their interaction on yield, yield components and sucrose of sugar beet plants (Beta vulgaris, L.). A split-split-plot design with four replicates was done. Experimental unit (sub-sub plot) was10.5 m² (1/400/fed) "3x3.5 m" including 5 ridges each of 60 cm apart and 3.5 long. The importance findings can be summarized as follows:The highest values of top yield could be obtained from diamond in the 1^st season and Gloria Cultivar in the 2^nd one. The optimum phosphorus fertilizer treatments were 48 kg P₂O₅fed^-1, thereby it caused a significant increase and the greatest values of top yield. Moreover, the response of sugar beet top yield to the interaction varietal effects X boron fertilizer levels was significant in the two seasons.  Phosphorus at a rate of 48 kg P₂O₅ was the best treatment among other phosphorus treatments, which resulted in the maximum root yield in the 1^st and 2^nd seasons. Furthermore, control treatment (without addition) recorded the lowest mean in the 1^st and 2^nd seasons, respectively. With expecting the impact of boron fertilizer effects on root yield, increasing its levels from 0 to 1.125 kg H₃PO₄ fed^-1 tended to increase root yield in the two growing seasons. Generally, the highest total yield achieved from Gloria cultivar with mean 30.72 Mg fed ^-1 while, Diamond cultivars recorded 28.44 Mg fed^-1 in the first season. Meanwhile, in the second season the same trend were observed for cultivars Gloria which surpassed cultivars Diamond.cultivars of beets, Phosphorus showed a significant increase in sucrose % and increasing boron fertilizer levels from 0 to 0.750 and 1.125 kg Borax/fed tended to increase sucrose % from 16.82 to 16.89 and 16.98 in the first season and 20.17, 20.23 and 20.30% in the second season, respectively. It could be concluded that all used treatments significantly affected on suger beet yield and its component. The interaction between Gloria cultivars, phosphorus fertilizer at the rate of 48 kg P₂O₅ fed^-1, boron at the rate of 1.125 kg fed^-1 recorded the best in all used treatments.