This study was conducted during the two successive seasons of 2013 and 2014 in a private orchard, at El-Kharga Oasis, New Valley Governorate, Egypt to investigate the effect of magnesium fertilization and leaf/bunch ratio on growth and fruiting of Sewy date palm. The experiment was set up in a randomized complete block design in split plot arranged. The pruning treatments were imposed in main plots while the magnesium fertilization rates were put in the sub-plots. Both pruning and fertilization treatments include three levels per each. The number of new leaf/palm, leaf area and leaf nutrient composition substantially increased with increasing leaf/bunch ratio from 6 to 10:1 leaf/bunch. Also, such growth traits materially increased with increasing magnesium levels from 500 to 1000 g/palm. All combinations of (MgSO₄) at 750 to 1000 g with 8 or 10 leaf/bunch induce a considerable increase in growth traits and nutrient content in the leaves of palms compared to using 500 g N/palm and leaving 6 leaf/bunch. Fertilizing by 750 & 1000 g/palm along with pruning to leave 8 or 10 leaf/bunch was followed by yield and fruit quality of Sewy date palm compared to using 500 g MgSO₄/palm and accompanied with leaving 6 leaf/bunch. Fertilizing the palm with 750 or 1000 g MgSO₄ improving combined with 8 or 10 leaf/bunch ratio had no major effects. It could be concluded that leaving 8 active leaves per each retentive bunch combined with fertilizing with 750 g MgSO₄/palm gave the best results with regard to yield and fruit quality of Sewy date palm.