A pot experiment was carried out on sandy soil at Mansoura Agricultural Rresearch Station during winter 2007-2008 to study the effect of biofertilization, compost and mineral nitrogen fertilization on microbial population and mycorrhizal infection in wheat Gemmeza 69 plants. Compost supplementation (0, 5 and 10 m³ /feddan), nitrogen mineral fertilization as ammonium sulphate (0, 60 and 120 kg N / fedden) and biofertilization using Azotobacter Azotobacter spp. + Azospirillum lipoferum, Cyanobacteria, mycorrhiza + Azotobacter chrococcum + Azospirillum lipoferum and mycorrhiza + Azotobacter Azotobacter spp. + Azospirillum lipoferum + cyanobacteria as well as the uninoculated treatmens were applied in wheat plants Gemmeza 69. Results indicated that compost supplementation increased total bacterial, Azotobacter, Azospirillum and Cyanobacteria counts as well as the percent of mycorrhizal infecetion. The same trend was observed with the nitrogen fertilizer levels. Bio-inoculation stimulated the microbial population in the rhizosphere region. The mixed inoculum of (Azotobacter, Azospirillum, Cyanobacteria and mycorrhiza) caused the highest number of total bacteria, Azotobacter, Azospirillum, and Cyanobacterial counts as well as the percent of mycorrhizal infection. The counts were high in the first sample which collected after 60 days after sowing (DAS) and in the second sample which collected 90 DAS, but counts decreased at harvesting stage. Mycorrhizal application increased the percent of infection noticed on wheat roots in comparison with non-application treatments. Inoculation with cyanobacteria increased the microbial population in comparison with control.