This study was carried out during 1997 and 1998 seasons. Alphonso mango trees of 20 year old were used. The experiment was conducted in an orchard located in Giza governorate. Panicles were sprayed at full bloom with putrescine at 150, 300 or 450 PPM, KNo₃ at 0.5, 1 or 2% and CPPU at 5, 10 or 15 PPM. The highest fruit number per panicle was recorded with putrescine followed by CPPU   hand a direct relationship was detected in this respect with putrescine. The highest fruit set was scored with both of putrescine and CPPU. Whilst, the lowest one was detected with KNo₃ . A direct relationship was found between putrescine concentration and fruit set, reversibly, fruit set decreased with the increase in CPPU and KNo₃ concentration. Fruit drop decreased with KNo₃ while it increased with putrescine and CPPU. Both of KNo₃ and putrescine increased fruit retention at harvest with a direct relationship with the used concentrations .The highest values in this regard were recorded with 2% KNo₃ and 450 PPM putrescine.