A comparative study of the effect of nitrogen deficiency on the physiological status and growth of young sunflower plants (Helianthus annuus L. cv. Biser) and corn (Zea mays L. cv. Knezha 613) was done. The experiment was carried out in a climatic room under controlled conditions. The plants were grown in pots as sand cultures in two variants: control plants grown in full-strength Knop nutrient solution and experimental group plants grown in Knop without nitrogen supply. The growth and physiological parameters were measured for corn and sunflower respectively two and three weeks after growing the plants under nitrogen deficiency conditions. A significant decrease in all measured parameters was recorded for the plants grown in nitrogen deprivation.