A field experiment was carried out at the Agronomy Department Farm, Faculty of Agriculture, Assiut University during 2017 and 2018 seasons to study the effect of plant density and nitrogen fertilizer splitting on the production of sunflower. The experiment was laid out in Randomized Complete Block Design
(RCBD) in split- plot arrangement with four replications. Plant density (46666, 28000, 20000 plants/fed.) were assigned in main plots and three treatments of nitrogen fertilizer splitting (2 and 3 doses) were arranged in sub-plots. The obtained results showed that plant height, seed weight per plant, seed yield (kg
fed‾ ˡ), oil percentage (%) and oil yield (kg fed‾ ˡ) were affected significantly by plant density in both seasons. Plant density 20000 plants /fed gave the highest mean values of seed yield fed‾ ˡ (2669.14 and 2569.59 kg /fed.) and oil yield fed‾ ˡ (990.47 and 915.21 kg/fed, in the first and second seasons, respectively). Additionally, Splitting nitrogen fertilizer into three doses (N1) gave the highest
mean values for mention traits in both seasons. There was significant interaction between plant density and splitting nitrogen fertilizer on all the studied traits in the both seasons, except plant height. Plant density 20000 plants /fed when received nitrogen fertilizer at three doses (N1) gave the highest mean values of seed yield fed. (2833.33 and 2728.58 kg/fed.) in the both seasons.