Two field experiments were conducted at Sers EL-Lian Agricultural Research Station (EL-Minufiya Governorate) during 2005 / 2006 and 2006 / 2007seasons to study the effect of some preceding summer crops (cotton, soybean and maize ) ,seeding rates (50, 60 and 70 kg seeds / fed )and  three treatments mineral and bio-Fertilization (70 kg mineral N/fed, 70 kg mineral N/fed + Cerialein500g/fed and 70 kg mineral N/fed + Cerialein750g/fed) / fed on grain yield ,yield components and protein yield of wheat cultivar Sakha 94. Split- split plots design with three replication was used. The results indicated that yield, yield components and protein yield of wheat recorded the highest values when wheat was sown after soybean followed by cotton and recorded the lowest values when sown after maize.  The results showed that plant height, number of spikes / m², spike length (cm), number of grains / spike as well as 1000- grain weight (g),  grain yield/fed  and protein yield were significantly increased by increasing seed rates in both seasons, except grain weight /spike and straw yield /fed were not significantly in the first season and the number of spikelets/spike in both seasons. Increasing mineral and bio- N fertilizer levels up to 70 kg mineral N/fed+ two package of Cerialein / fed, significantly increased all characters, except number of spikelets /spike. The highest values of these characters were obtained with 70 kg mineral N/fed + 750g Cerialein / fed) .The application of 70 kg mineral N/fed resulted in the lowest values in both seasons. Results also, indicated that interaction between preceding crops and seeding rates significantly affected on spike length, protein yield /fed and grain yield/fed in both seasons, number of spikes / m² , weight of grains / spike and 1000-grain weight in second one. Also, the interaction between preceding crops and mineral or bio-N fertilization significantly affected on grain yield/fed and protein yield /fed in both seasons and 1000-grain weight in the second one only.