Afield experiment was conducted twice at the farm of the Environmental Studies and Research Institute, Minufiya University, Sadat City (Minufiya Governorate), during the two successive winter seasons of 2006/2007 and 2007/2008 to study the response of faba bean (Vicia faba L. cv. Giza 461 ) to inoculation with Rhizobium leguminosarium individually or mixed with rhizobacteria known to produce plant growth- promoting substances (PGPR), i.e., Azospirillum brasilense , Bacillus megaterium or Bacillus polymyxa  as co inoculation under three levels of mineral nitrogen fertilizer ( 0 , 20 , 40 kg N /fed ), in a newly reclaimed desert (sandy soil).       Results showed that nodulation, plant growth parameters and bacterial activities in soil, varied depending on nitrogen dose and introduced bacteria. Co-inoculation with Rhizobium and PGPR resulted in significant increases in number and dry weight of root nodules, as well as nitrogenase activity of the root system as compared with the single inoculation with Rhizobium alone or control (un-inoculated plants). Mixed inoculation improved bacterial activities in rhizosphere soil, dehydrogenase, and phosphatases (acid and alkaline) enzymes and total bacterial count, compared to the single inoculation. In respect to nitrogen fertilizer , the highest rate applied( 40 kg N /fed.) gave the maximum value of bacterial activities, as compared with the other doses, except nitrogenase activity, which was favored with the lower N dose(20 kg ).      The parameters of faba bean growth, seed yield and its attributes were generally promoted with the applied treatments, i.e., the biofertilizer significantly enhanced plant growth rate and parameters at 40 D and 85 days age. Mixed inoculation (R.l.+ B. polymyxa) produced the highest values of plant height , shoot and root dry weights. The same treatment exhibited the greatest number of branches, number of pods, number of seeds / pod, seed index and seed yield /plant, and consequently highest seed yield /fed ,e.g., average increase in yield /fed. was (67.45% & 63.62%) for the two seasons, respectively. No significant differences could be detected between the two doses of nitrogen fertilizer (20 and 40 kg N/fed.) in most studied traits, except seed yield per plant and per fed. Inoculation with R.l. + B.megaterium or B. polymyxa combined with 40 kg N/ fed. resulted in the highest values of most studied traits, except the nitrogenase activity, which was higher with 20 kg N/fed.