This work was carried out during the two summer seasons of 2004 and 2005 at Arab El-Awammer Research Station; Center (A.R.C.); Assiut Governorate, Egypt, to study the effect of using biofertilization to decreased the chemical fertilizer rates on sweet potato plants grown in newly reclaimed soil under drip irrigation. Four lines of sweet potato (Assiut 201,202,203 and 204) and five treatments of nitrogen zero, 25,50,75 and 100% from the recommended dose used with an equal amount of  Biogen fertilizers (2Kg) in our study. The results indicated that the treatment of (100%N+2Kg Biogen) gave the best results in most studied characters and also lines Assiut 201 and 204 were the best lines under experiment condition for most studied characters. The 100% N level with Biogen fertilizer gave the best results in most characters. Also the interaction between (100%N +Biogen) and line Assiut 204 gave the highest plant height and highest number of branches while the interaction between 100%N+ Biogen and line Assiut 201 gave the best number of marketable storage root/plant, weight of marketable storage root/plant, root length and root diameter. While the high starch root percentage was obtained from interaction between 25 and 75%N+Biogen and line Assiut 201.