Pistachio trees exhibit some such physiological problems as abscission of inflorescence buds, fruit fall, the incidence of blank, non-split, early split and deformed nuts. The occurrence of the problems would be closely related to diminishing yield. In this study, the effect of Putrescine (Put), Spermidine (Spd) and Spermine (Spm) on these shortcomings and on the yield of "Kalle-Ghooochi" pistachio was investigated in two consecutive (“on” and “off”). Free Polyamine treatments were applied one week before and two weeks after full bloom. Results showed that Spm, unlike Put, decreased the physiological shortcomings of the fruit and increased yield. Spd treatment decreased the percentage of both fruit abscission and deformed nuts, but did not affect yield. In any of the “on” and “off” years, the effect of Spm and Spd was greatly dependent on both the time of application and on the concentrations used. It seems that application of Spm dominantly plays a key role in controlling the abscission of inflorescence buds and also in improvement of growth and development of pistachio nuts resulting in increase in the yield on pistachio tree shoots.