A field experiment was conductedto know theeffect of Plant Growth Promoting Rhizobacteria (PGPR) and PSB on root parameters, nutrient uptake and nutrient use efficiency of irrigated maize under varying levels of phosphorusduring kharif, 2015 at College of Agriculture, V. C. Farm, University of Agricultural Sciences, Bangalore. The experiment comprised of thirteen treatments consisting of three levels of phosphorus (75, 100 and 125 per cent of recommended dose) and various phosphorus bio-fertilizers and Plant Growth Promoting Rhizosphere (PGPR) and their combinations. The experiment was laid out in RCBD with three replications. The soil type was sandy loam. The maize hybrid NAH-1137 was used. The results revealed that, the application of 75, 100 and 125 per cent of recommended dose of phosphorus fertilizer along with PGPR II (Pseudomonas fluorescens + Bacillus megaterium + Azospirillum brasilense) increased the root parameters viz., root length, root volume and root biomass as well as yield over control. The kernel yield was significantly higher over control in all the treatments involving bio-fertilizers except with the application of 75, 100 and 125 per cent of recommended dose of phosphorus fertilizer along with Bacillus megaterium. Application of 75 per cent of recommended dose of phosphorus fertilizer along with PGPR II recorded high nutrient uptake as well as nutrient use efficiency. A combination of both PSB and N-fixing bacteria (PGPR II) has improved the root growth and yield in maize than PGPR I (P. fluorescens + B. megaterium).