Two field experiments were carried out at the Experimental Farm of the Faculty of Agriculture (Saba Basha), Alexandria University, at Abees region, Alexandria, Egypt during the two successive growing seasons of 2012 and 2013 to study the effect of mineral- organic N- fertilization and inoculation with phosphate solubilizing microorganisms on growth and yield of sorghum (Sorghum bicolor L., cv. Dorado). The applied experimental design was split plot with three replicates. The main plots were conducted for the three mineral- organic manure fertilization (100% N, 75 % N + 25% organic and 50 % N + 50 % organic), while the uninoculation + 100 % P, phosphorein + 75 % P, A- Mycorrhizal + 75 % P and phosphorein + A- Mycorrhizal + 75 % P), which were arranged in the sub- plots. The main results could be summarized as follows: (1) The mineral- organic at (50% N + 50% organic), gave the highest mean values of all studied characters, also (2) The mixed biofertilizer inoculation (A- Mycorrhizal + Phosphorein) + 75 % P was the best treatment to obtain the highest mean values of plant height leaf area index, stalk diameter, no. of branches/head, Total chlorophyll, grain yield, yield components N, P and K%. However, all traits under this study increased, significantly, due to inoculation treatments over “uninoculation + 100 % P".  The investigation suggests the need to more studies concerning the effect of biofertilizers and their interaction, as well as applying micronutrients on sorghum plant under different environments using different types of soil to reach the optimum combination to achieve the highest sorghum yield and its quality.