The residual effect of paclobutrazol (PBZ) was investigated on mango Zebda cv. during "On" and "Off" years; 2004 and 2005; after application on October 2003 and 2004.                 The result showed that PBZ application at 15 and /or 20 g/tree as a soil drench induced suppressed vegetative growth, early flowering and yield, controlled alternate bearing, increased fruit weight and yield as well as enhanced fruit quality in both "On" and "Off" years during 2004 and 2005 seasons.  In addition the same treatments suppressed vegetative growth, increased No. panicles per tree, No. hermaphrodite flowers/panicle, No. fruits per panicle and No. fruits per tree compared with untreated trees (control) on "Off " year during the two seasons of study. On the other hand, application of PBZ  had no effect  in seed weight %, pulp/seed ratio, acidity % and V.C. (mg/100g pulp) during "On" and "Off" years.