This investigation was conducted during 2018 and 2019 seasons at Abu El-Matamir, El-Beheira governorate, Egypt on “Kelsey" plum trees. The trees were eight years old, budded on Mariana rootstock, planted at 4 × 5 meters apart in calcareous soil under drip irrigation system. Foliar spray of sitofex (CPPU) at 0, 2.5, 5, 7.5, 10, 12.5 and 15 ppm were done twice at full bloom and after two weeks from full bloom to assess their effect on yield and fruit quality during storage at 0 ±1°C with 90 ± 95% RH for 28 days. The results showed that, foliar spraying of "Kelsey" plum trees with sitofex (CPPU) at concentration of 10, 12.5 and 15 ppm significantly enhanced fruit set and reduced fruit drop as well as produced high yield with heaviest and largest fruits reached at harvest stage. Moreover, these three concentrations were the most effective treatments maintaining the quality characters during cold storage at 0 ±1°C with 90 ± 95% RH showing the lowest fruit weight loss and decay. Also, these three concentrations gave the highest fruit firmness and maintained SSC%, acidity, SSC/acid ratio and ascorbic acid content till 28 days of cold storage. It could be storage recommended that spraying "Kelsey" plum trees with sitofex at 10 ppm twice at the full bloom and after two weeks from full bloom which is considered the best and economic treatment used for enhancing flowering, producing maximum yield and improving fruit quality particularly fruit size as well as maintaining the overall quality of “Kelsey" plum fruits during storage at 0 ±1°C with 90 ± 95% RH for 28 days.