A field experiment was conducted during the spring season of 2024 at the College of Agricultural Engineering Sciences - University of Baghdad, to study cultivation sustainability of sunflower influenced by nitrogen fertilization and bacterial biofertilization. A split-plot arrangement within randomized complete block design with three replications was used. The main plots received 0, 25, 50 and 75% of recommended nitrogen, while the sub-plots were sown with seeds inoculated with Azotobacter chroococum, Azospirillum brasilense, their mixture and without inoculation, in addition to application of recommended nitrogen fertilization (200 Kg N ha^-1) for later comparison with fertilizer combinations. The Findings showed that application 75% of recommended nitrogen fertilizer was significantly superiority in the leaf area (50.21 dm²), fertility rate (71.95%) and seed productivity (5.577 Mg ha^-1). Also, there was a significant increase in the vegetative growth when seeds were inoculated with bio-fertilizer mixture, which led to an increase seeds number (1347.6 seeds head^-1) and seed productivity (5.406 Mg ha^-1). Significant interaction influence noted on most measured parameters. Regarding the comparison of fertilizer combinations with application of 200 kg N h^-1, it was observed that the inoculating seeds with bio-fertilizer mixture or alone reduced about 25% of nitrogen fertilizer recommendation.