Two pot experiments were conducted in the greenhouse of the National Research Centre, Dokki, Cairo, Egypt during 2004 / 2005 and 2005/2006 winter season to evaluate the effect of spraying with alpha - tocopherol and potassium di-hydrogen phosphate on growth, yield , and endogenous hormones of onion plants . There was a negative relationship between salinity and growth characters. The highest depression was detected in whole plants fresh weight irrigated by 5000 ppm whereas the lowest was in top height by 2500 ppm salt level in water of irrigation. The depression in top height and number of green leaves  caused by the higher salt level reached about one fold that caused by use of the moderate level of  salts, however, the decrement in fresh weight of leaves reached 2-5 fold that caused by the moderate level compared to plants irrigated regularly by fresh water. Top height, number of green leaves and whole plant fresh weight did not show any significant effect neither with alpha-tocopherol or alpha - tocopherol + potassium di-hydrogen phosphate fertilizer. Nevertheless, significant response was detected on dry matter of bulbs.      Increasing in salt stress negatively affected the concentration of IAA, GA and cytokinins in leaves of onion plants. However, subjected plants to salinity at level of 2500 ppm slightly affected but sharply depressed these three growth hormones by the high salt stress used i.e. 5000 ppm. Nevertheless, the concentration of ABA showed a pronounced   increase as a result of exposed onion plants to   continuous increases in salt concentration.         Neither IAA or cytokinins concentration affected by spraying alpha -tocopherol with or without potassium di-hydrogen phosphate foliar fertilizer, however, GA concentration slightly increased by alpha - tocopherol application  in the rate of  100 ppm and tended to decrease to be equal with the concentration of this hormone in the control plants when plants sprayed by alpha - tocopherol plus potassium di-hydrogen phosphate. Furthermore, the concentration of ABA still without changes with alpha - tocopherol treatment and increased by alpha -tocopherol + potassium di-hydrogen phosphate foliar fertilizer compared with the unsprayed plants.