The present study was conducted on squash plants during the summer of 2006 and 2007 seasons at the Experimental Farm, Faculty of Agriculture, Suez CanalUniversity, Ismailia governorate to study the effects of foliar spray with vit. C, IBA, BA, kinetin and Isatin at various concentrations on squash vegetative growth, leaf pigments, leaves chemical composition, yield and its components and fruit quality under sandy soil condition. Foliar spray with 50, 100 or 150 ppm Isatin gave rise to the highest values of plant length, number of leaves, fresh weight of leaves, fresh weight of stem, total plant fresh weight, dry weight of leaves, dry weight of stem, total dry weight as per plant basis, as well as N, P and K contents. In addition foliar spray    with 100 and 150ppm Isatin gave the greatest contents of chlorophyll a, b and total chlorophyll as well as carotenoids. Moreover, 150ppm Isatin gave the highest values of number of fruits per plant, marketable and unmarketable yields and total yield. Foliar spray with vit. C at the concentrations of 150 and 300ppm gave the greatest vit. C content of fruits while Isatin at the concentration of 50, 100 or 150ppm gave the greatest carbohydrate content of fruits. Furthermore, irrespective of substrate concentration. Application of vit. C, BA, kinetin or Isatin gave higher values of the previous characters than foliar spray with disttield water (control).