Two felid experiments were conducted at the Experimental Station Farm, Faculty of Agriculture, Mansoura University, Egypt, during two summer seasons of 2014 and 2015 to study the effect of irrigation intervals (7, 10 and 15 days), organic fertilizers (Without compost – With compost), antioxidant treatments as a foliar applications (Control – Yeast - Ascorbic acid and Salicylic acid) and their interactions on chemical constituents, yield and fruit quality of summer squash (Cucurbita pepo L.) cv. Mabroka. Obtained results indicated that chlorophyll pigments, nitrogen, phosphorus, potassium, total soluble solids, vitamin C, nitrate, nitrite, crude protein, total carbohydrates, crude fibers, total fats, dry matter percentage, early and total fruits yield ton/fed were significantly affected by irrigation intervals, organic fertilizers with compost and foliar spraying with antioxidants treatment. Irrigation intervals every 10 days gave the highest values of measured parameters in both seasons followed by irrigation every 7 days as well as fertilization with compost 15 m3/fed and foliar spraying with antioxidants increased all studied fruit qualities compared with untreated plants in both seasons except, nitrate, nitrite, crude fibers. Meanwhile, the interactions among treatments showed that the highest values of all previous measurements were recorded when plants irrigated every 10 days and fertilized with compost (15 m3/fed) as well as foliar spraying with yeast extract (2g/L) except, nitrate, nitrite, crude fibers comparing to other treatments. Therefore, this treatment can be recommended to increase the quantity of the yield and improve the fruits quality and reduce the amount of irrigation water used.