This study was conducted on 23-years old plum trees (Golden Japanese, Dorado and Santa Rosa cultivars) budded on Mariana rootstock and planted at 5  5 m apart on clay loamy soil under flood irrigation system (5180 and 5124 m3/feddan/season) or drip irrigation system (2607.4 and 2553.6 m3/fed./season) during 2010 and 2011 seasons, respectively. Drip irrigation system supported an increase of vegetative growth parameters (shoot length, leaf area, leaf dry weight %, number of leaves/shoot and foliation %), fruit attributes (flowering %, fruit set, number of fruits/tree and yield), fruit quality (weight, size, firmness, TSS and acidity), root length, root dry weight (roots < 2 mm and 2-6 mm) and water use efficiency (1.94-2.5 kg/m3 fruits). While flood system increased leaf dry weight %, root dry weight (roots > 6 mm), as well as narrow and broad-leaf weeds spread. However some of these differences were not significant. Golden Japanese plum cv. produced higher fruit set, yield, number of fruits/tree, as well as water use efficiency and less fruit juice acidity. While Santa Rose cv. resulted better foliation, fruit weight and size, as well as juice TSS and more suitable fruit firmness. Meanwhile larger leaves with much dry weight % and less fruit drop were proceeded from Dorado plum cv. So we can recommend plum growers on clay loamy soil to converse flood irrigation system to drip system to save 50.1 % of irrigation water with better growth, fruit yield, fruit quality, much water use efficiency and to reduce weed spreation.