Two field experiments were conducted during summer seasons of 2005 & 2006 to evaluate response of sunflower plants (Helianthus annus L. cv. Sakha 53) grown in sandy calcareous soil to fertilization with mineral and organic nitrogen as well as inoculation with biofertilizer •Phosphorein and to four N-fertilization treatments: 60 kg mineral N/fed, 60 kg organic N/fed, 30 kg mineral N/fed + 30 kg organic N/fed and 60 kg mineral N/fed + 30 kg organic N/fed. Biofertilizer increased plant growth, nitrogen and phosphorus uptake significantly. An increase in seed yield (10.6%) and oil yield (11.1%) was recorded. The treatment of 30 kg mineral N2 + 30 kg organic N2 / fed attained pronounced increase of plant growth, N and P uptake. Seeds and oil yields being 18.9 and 18.8% respectively in comparison with the control were determined.