The effect of nitrogen fertilization levels  (60, 75, 90 and 105kg N/fed) and sources (urea and Ammonium sulphate) on yield and its components of two wheat varieties (Giza 164 and Sakha 69) was investigated at the Agriculture Experimental and Research Center, Faculty of Agriculture, Cairo University at Giza, Egypt during 1996/97 and 1997/98 seasons .                 Differences in grain and straw yields as well as their related variables due to changing N levels were significant in both seasons.  Application of the highest N level (105 kg N/fed) produced 2.3 (13.4%) and 1.8 ard/fed (10.2%) more than the application of N at the recommended dose (75 kg N/fed) in the first and second seasons, respectively. With regard to the N sources, the highest values resulted from application of N as urea, while the lowest one produced by ammonium sulphate in both seasons.                  Varieties had a significant effect on plant height, number of grains/spike and grain yield/fed in both seasons and number of tillers/m², number of grains/spike and 1000- grain weight  in one season only. As an average of both seasons, Sakha 69 outyielded Giza 164 in grain yield by 1.6 ard/fed and in straw yield by 0.6  ton/fed                 The interaction of varieties x N levels had a significant effect on plant height, and 1000- grain weight in both seasons and on spike length and number of grains/spike in one season. Moreover, varieties x N levels x N sources interaction had significant effect on either grain or straw yield/fed in both seasons. As an average of both season the highest grain yield/fed (26.55 ard) was obtained by using Sakha 69 variety and 105 kg N/fed as urea.                 Consequently, it could be concluded that under the conditions of this study the highest wheat production from either grain or straw can be produced with using Sakha 69 variety and application of 105 kg N/fed as urea.