This investigation was carried out for two successive seasons (1997 and  1998 ) on “ Picual" olive trees grown at Rafah ,Northern Sinai Governorate . The experiment included three Levels of potassium sulphate fertilization (namely 300,400 and 500 gm / tree/ year). Each level was added at one or two equal doses during the growing season.          Results showed that the highest yield was produced by 500 gm. potassium sulphate/ tree/ year, applied at two equal doses in the two season of study. Fruit weight, volume, length, diameter and flesh/ Fruit ratio were significantly affected by different treatments specially potassium fertilization at 500 gm. added at two equal doses/ year.