Two field experiments were conducted at the Extension Field near Nit Ghmr. Dakahija Governorate to evaluate effects of rates and application treatments of the ferti lizer N on growth and productivity of sunflower in 1967 and 1968 seasons. Rates were 0, 20, 40 and 60 kg N/fad. Appli cation treatments were six dose—time combinations. Results obtained showed that N significantly affected at least six growth characters out of nine. These were mid—flowering date, plant height, number of groen leaves/plant, number of dry leaves/plant, stem diameter and leaf area (LA). N had unfavourable effects on percentages of lodged and broken plants, which were both increased by N rates. No signifi cant differences were detected among rates except for plant height in favour of 60 kg/fad. and the number of dry leaves/plant in favor of 20 kg N/fad, in one season only. LA increased significantly with 60 kg N/fad in both seasons. Results obtained suggest that the rate equals to 20 kg N/fad. could be considered sufficient for supporting good growth of sunflower in that niche. Dose—time combinations were about equal In their effects. In addition, no signifi cant interaction of rate dose—time combination was detected indicating the independence of both factors in effect.