The present investigation was conducted at El-Hamoul area, Kafr El-Sheikh Governorate, Egypt during 2000/2001 and 2001/2002 seasons, to study the effect of three nitrogen sources (urea 46% N, ammonium nitrate 33.3%N and ammonium sulphate 20%N),  two rates (60 and 90 kgN/fed) and three application time of nitrogen (All nitrogen rates of the three sources were applied at 40 or at 70 days from sowing and splitted into two equal half  the first applied at 40 and  the second at70 days after sowing)on growth, yield and quality of sugar beet, cultivar Top poly.The experiments were carried out in randomize complete block design in factorial arrangement with three replications. The obtained results showed that the effect of nitrogen sources was significant on root length , root fresh weight, sucrose %, root yield/ fed and sugar yield /fed in both seasons. Ammonium nitrate gave the highest values of all previously mentioned traits as compared with other studied sources in both seasons. The obtained results showed that the effect of nitrogen rates was significant on all studied traits in both seasons. Applied nitrogen fertilizer at the rate of 90 kgN/fed surpassed 60kgN/fed in all studied characters in both seasons. The obtained results indicated that the effect of nitrogen application time was significant on all studied traits in both seasons, except sucrose% in 2001/2002 season. Splited  nitrogen fertilizer into two equals half an added at 40 and 70 days from sowing  gave the highest values of all studied traits in both seasons.                 The results presented  exhibited that all the interaction effects between the three studied factors were  significant on root fresh weight  in both seasons. The interaction effect among sources and application time of nitrogen  and the interaction effect among  rates  and application time of nitrogen were significant on root and sugar yield/fed in both seasons.