THIS INVESTIGATION was undertaken to study the effect of foliar spray with Ca and B at different concentrations on some fruiting parameters and fruit characteristics as well as leaf nutritional status of "Kelsey" plum trees. Trees were twenty-years-old, planted at 5 meters apart and budded on Mariana rootstock grown in El-Kanater Horticulture Research Station during 2008 and 2009 seasons. 
Obtained data indicated that most of Ca and/or B foliar spray either alone or in combinations at different concentrations resulted in a positive and significant increase in fruit set % and tree yield /feddan and yield increment % compared with the control. Whereas decreased the percentage of fruit drop in both study seasons. Moreover, fruit physical properties (weight, volume, firmness, dimensions and fruit shape index) and chemical characters (TSS %, acidity % and TSS/acid ratio) were significantly improved as a result of the highest rates of both Ca and B foliar spray treatments either alone or in combination compared to the control. In addition, leaf nutrient content of some macroelements (N, P, K, Ca and Mg) and some micro-nutrients (Fe, Zn, Mn and B) were generally increased with the different treatments during both 1st and 2nd seasons of study. 
Undoubtedly, it could be concluded that, foliar applications of (Ca) and (B) either alone or in combinations exhibited a positive and a significant influence on fruit quality of "Kelsey" plum trees. However, the highest concentration of (Ca2 x B2) treatment was the most effective in improving most fruit physical and chemical properties as well as leaf nutritional content of "Kelsey" plum trees.