Microbes that are beneficial to plants are used to enhance the crop growth,yield and are alternatives to chemical fertilizers.Trichoderma and Bacillus are the predominant plant growth-promoting fungi and bacteria.The objective of this study was select,characterize,and evaluate isolates of Trichoderma spp.and Bacillus spp.native from the northern region of Sinaloa,Mexico,and assess their effect on growth promotion in maize(Zea mays L.).In greenhouse conditions,four Trichoderma isolates and twenty Bacillus isolates,as well as two controls,were tested in a completely randomized design with three replicates.We selected the two best strains of Trichoderma and Bacillus:TB=Trichoderma asperellum,TF=Trichoderma virens,B14=Bacillus cereus sensu lato and B17=Bacillus cereus,which were evaluated in the field in a completely randomized blocks in factorial arrangement design with three replicates applying different rates of nitrogen fertilizer(0,150 kg N/ha,and 300 kg N/ha).Treatments 5(B17=B.cereus)and 11(TF=T.virens)both fertilized with 150 kg N/ha showed similar yields and they did not reveal significant differences from the treatments fertilized with 300 kg N/ha.This indicated that treatment 5(B17=B.cereus with 150 kg N/ha)and treatment 11(TF=T.virens with 150 kg N/ha)were efficient as growth promoters,by not showing significant differences in root volume and dry weight of foliage.The results indicated a reduction of 50% in the rate of nitrogen to fertilizer required for maize(Zea mays L.)crops.These microorganisms Trichoderma and Bacillus could be an alternative to reduce the use of chemical fertilizers in maize.