Water is critical factor affecting plant growth and development, where its time and quantity of application plays an important role in increasing the yield levels with saving water, especially in sandy soil with low water holding capacity. Optimum irrigation level would help in improving the economic yield as well as water use efficiency. Sunflower (Helianthus annuus, L.) is one of these plants that affected by water supply according to its huge vegetative growth and transpiration area. It is essential edible oil in many countries all over the world, which ranks the fourth position next to groundnut, soybean and rapeseed. So, this study aimed to investigate the effect of four levels of irrigation (I₁=1.2, I₂=0.9, I₃=0.6, I₄=0.3 m³day^-1/plot area) and five sunflower genotypes(G₁=P.L120, G₂=P.L125, G₃=P.L240, G₄=P.L770 and G5=P.L990) and two cultivars Sakha-53, Giza-102under North Sinai conditions during 2016 and 2017 seasons. In this study, there were 28 treatments (4 x 7). The Results indicated that seed head weight gave the highest values (100.00&109.00 g)and obtained from I₃×G₄ at both seasons.However,100 seed weight were 10.66 and 10.67 g and obtained from I₁×G₄ and I₂×sakha 53 at 2016 while, at the second season the values 11.00 g and obtained from I₁×G₄, I₂×G₅, I₃×G₃,G₄ and Giza 102, I₄×Giza 102.