A two-year field experiment was conducted in Etay El-Baroud Experimental Research Station, El-Beheira Governorate, Agricultural Research Center (ARC), Egypt, during 2018/2019 and 2019/2020 seasons to investigate the effects of preceded  winter crops with organic (FYM) and mineral nitrogen (N) fertilizers on yield and its components, as well as seed quality of sunflower. This study included twelve combinations between three preceded winter crops (flax, wheat, and onion) and four fertilizer treatments (T1: (50% N + 50% farmyard manure, T2: 75% N + 25% farmyard manure, T3: 100% N and T4: 100% farmyard manure). A split-plot design with three replication was used. Three preceded winter crops were randomly assigned to the main plots, and four fertilizer treatments were allotted in sub plots. The preceding crops had a significant effect on most yield and yield components, the highest values (3.007 and 3.275 ton/ha) were obtained when sunflower grown after onion in the first and second seasons. Fertilizer treatments had a significant effect on number of seeds/head, 100-seed weight and seed yield/ha. The highest values (2.787 and 2.962 ton/ha) of seed yield of sunflower were obtained when the T1 treatment was applied at the first and second seasons. Growing sunflower after onion decreased percentage of two saturated fatty acids (palmitic acid and stearic acid), while increased the percentage of the 2 essential unsaturated fatty acids (oleic acid and linoleic acid ), protein content and oil content, compared with sunflower grown after flax or wheat. The highest values of oleic acid (49.95 and 50.28%) and linoleic acid (35.81 and 37.86%) were observed by applying of T4 in both seasons. The highest palmitic acid values of (8.61 and 8.77%) and stearic acid (8.14 and 7.77%) were observed by fertilizing of T3 in both seasons, respectively. The fertilizer treatments of sunflower (T1 and T4) increased the percentage of unsaturated fatty acids/ saturated fatty acids%, while T3 decreased this percentage. Application of sunflower by 50% N + 50% FYM after onion uprooting can be recommended for increasing productivity and seed quality of sunflower.