Abstract: Effect of bio- and chemical fertilizers, separately and in different combinations, on the growth of sunflower (Helianthus annuus L.) was studied to reduce the chemical fertilizers used, maximizing their use efficiency and to obtain highest growth and productive parameters. The biofertilizers used as inoculums for seeds treatment of sunflower cv. Geza 1 were Azospirillum (nitrogen fixing bacteria, N.F.B.) and Bacillus polymyxa (phosphate dissolving bacteria, P.D.B.) and their mixture. Both bacterial inoculants and their mixture show an increase in growth parameters, nutrients content and yield when compared to the control (full dose of NPK chemical fertilization). The result reveals that biofertilization treatments of Azospirillum + Bacillus plus 100% chemical fertilizers produced the highest values in all growth and yield parameters compared with the control (full dose of chemical fertilization alone). The results also indicated that biofertilization, beside its ability to improve the nutrient supply in the soil, also increases the efficiency of added chemical fertilization.