This experiment was carried out during two successive seasons (2002-2003 and 2003-2004) on Washington navel orange trees 30 year old grafted on sour orange grown in a private orchard in Elkaliobia Governorate to explore the possible effects of foliar application of gibberellic acid at 10, 15, 20ppm and calcium chloride at 1% and2% on the quality of on-tree-stored fruits of Washington navel orange.  Treatments were applied at fruit color break as whole tree sprays .Fruits were harvested at four dates January, February, March, and April. Yield and fruit quality parameters were recorded. Gibberellic acid at 20ppm significantly decreased the reduction in fruit weight, fruit drop and increased juice weight percentage, juice acidity, ascorbic acid. Nevertheless GA₃ at all the tested concentrations minimized the peel thickness in the last harvesting date and decreased juice T.S.S Calcium chloride at 2%caused significant increases in fruit weight, juice weight percentage, juice acidity, ascorbic acid  and insignificant increase in peel thickness while it significantly decreased number of fruit dropped and juice T.S.S