This study was carried out during the two successive seasons of 2015-2016 and 2016-2017 at Kaha Research Station, Horticulture Research Institute (HRI), Agricultural Research Center (ARC), Ministry of Agriculture, Egypt under low plastic tunnel to study the effect of grafting to resist low temperature in winter season the effect of grafting on vegetative growth, yield, and fruit quality of two squash hybrids (Cucurbita pepo L.) ‘Aziad and Raad'. Squash transplants were grafted on three rootstocks namely Lagenaria siceraria Standl (Lg), Cucurbita ficifolia (Cf), Cucurbita moschata (Cm) and self-grafted squash transplants used as a control. All transplants were grown under low plastic-tunnel conditions. The results showed that vegetative growth characters i.e., plant height, number of leaf per plant and leaf area were significantly increases when ‘Aziad' hyprid was graftedon Cucurbita moschata (Cm) in both seasons. The same results were obtained with the characters of fruit quality i.e. number of marketable fruits/plant, marketable fruit weight/plant, V.C., carbohydrates, free proline and total chlorophyll. While, there were no significant differences realized when Aziad or Raad'grafted on the others rootstocks (Lg and Cf) compared with self-grafted plants (control) on leaves dry weight, average of fruit weight, Ca%, dry weight of 100g fresh fruit, TSS and total carotenoids.