In 1993-1994 four exact field experiments dealing with nitrogen nutrition of sugar beet were carried out. The contents of available nitrogen (N-NO₃) in soil were supplemented before seed sowing: in first (control) object to the level 110 mg N-NO₃ (as nitrates) per dm³ and in other objects (2, 3, 4) to the level 50 mg N-NO₃ per dm³. The rest of nitrogen was supplied by foliar application and top dressing (4 objects). These experiments were carried out at Leszno near Warsaw and at Pałczyn near sugar factory "Środa". The results of four field experiments did not show any significant differences in root and sugar yields. The content of sugar did not increase essentially in first or other objects. The highest effect was obtained in case of foliar application which contained 1/6 of nitrogen top dressing dose.