Droughtisthe most commonenvironmentalstressesthatlimitscrop productionin25% of agricultural lands inthe world'sandis consideredas the most importantfactor inreducingcrop yield. Soilaggregate stability isalsoan importantpropertywhich controlsplant growthin aridandsemi-arid regions.Therefore, finding effectiveapproachesto increaseplant resistancetodroughtandimprove soil structureis of greatimportance. Rootsinoculatedwithusefulsoilmicroorganismscan be considered asan effective strategyfor reducing detrimental effects ofstressandimprove soil structure. This research was conducted in research greenhouse of Isfahan University of Technology to investigate the influence of individual and combined inoculation of endophytic fungus, Piriformospora indica , mycorrhizal fungi ( Glomus intraradices ) and plant growth-promoting rhizobacteria, Pseudomonas fluorescens onsomegrowthparameters ofmaize(single cross 704) andsomephysical propertiesofsoilseriesKhomeinishahr underdroughtstress.Greenhouse experiment using acompletelyrandomizedfactorial design with treatments includingmycorrhizal fungi(inoculated andnon-inoculated), P. indica (inoculated andnon-inoculated),bacterium(inoculated andnon-inoculated) andthree levels ofdrought stress(80%, 50% and25% ofavailable water) were performedin tree replicatesat Isfahan University of Technology. The results showedthatwithincreasingdrought stress(decrease of soil waterfrom80%AWto25%AW),cornfresh and dry weights, andshoot heightdecreasedsignificantlyinall treatments. Reducedsoilmoistureincontrol treatment decreased content of thephosphorusshoots of corn, butthe shootspotassium of shootsand proline contentof leaf inthistreatment increasedsignificantly. Also soil water repllency (WR) and mechanically dispercibleclay (MDC)significantly decreased by reducingsoilwater, but water sorptivityandmean weight diameter of aggregate(MWD)increased. Plant inoculationwithmycorrhizal fangusatalllevels ofdrought stress, P. indica onlyatthe third levelof stress(25%AW)andbacteriumat thefirst and second levelsof stress(80%AWand50% AW), increasedsignificantlyshoot dry weightin comparison to control. Inoculation of plant withmycorrhizal fungiatalllevels of stress,bacterium and P. indica atthefirst and second levels of stress(80%AWand50%AW)increased shootfresh weightcompared to thecontrol. Individualinoculationwithmycorrhizal fungiandbacteriumsignificantlyincreasedshoot height at all levels of stress. While, theheightof theplantsinoculatedwith P. indica significantly increasedonlyinthe firstandthirdlevels of stress. No significant differences were found betweencontent ofshoot potassium ofinoculated plantwithmycorrhizal fungi and control treatment at all levels of stress. Butindividualinoculationwithbacteriumand P. indica significantly increasedconcentration of shootK in compared to the control atthe first and thirdlevelsof drought stress. Plantsinoculatedwithmycorrhizal fungihadhigher phosphorusthancontrol and plant inoculated individually with bacterium and P. indica at all levels of stress. Whileindividualinoculation with P. indica onlyatthe third levelof stress(25%AW)andbacteriumat thefirst and second levelsof stress(80%AWand50%AW), significantlyincreasedshoot phosphorous contentin comparison to control.Individualinoculationwith any studied microorganismssignificantly resulted in higher proline than the control treatment at all level of stress.The results showedthatmycorrhizal fungiatalllevels of stress and P. indica at thesecond and third levelsweresignificantly increasedsoilwater repllency, Whilebacteriusmatalllevels of stress reducedWR, this reductionwas not significantinthe third levelof stress.Inoculation of each microorganismsindividuallyhad notsignificant effect onMWDat the optimummoistureconditions. Butwithincreasingdrought, themicroorganismshadincreasing effect onMWD. IndividualInoculatinon with P. indica andbacteriumtreatment atalllevel of stress andmycorrhizal fungi inoculation only attheoptimal level ofmoisturesignificantly decreaseddicpesible claycontent.Themost effectivetreatmentin reducingDCandincreasingMWD at the optimal level ofmoisture was mycorrhizal fangus, while P. indica was themost effective at thesecond and thirdlevels of stress. The most effectivemicrobialtreatmentin increasing shoot dryweight, height, P, leafproline and WR at the optimal level ofmoisture was belonged to co-inoclution ofmycorrhizal fangus and P. indica . Generally, corn Rootsinoculationwithusefulsoilmicroorganismscan be considered asan effective strategyfor reducing detrimental effects ofstress (particularco-inoclution ofmycorrhizal fangus and P. indica )andimprove soil physical properties.