Resumo. In the Rio Grande do Sul state, where eucalyptus reforestation is common in low fertility soils, the seedling performance may depend on the ectomycorrhizal association. In this paper, the inoculation effects of UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 ectomycorrhizal fungi isolates, individually and in mixture, on Eucalyptus grandis seedlings were evaluated. Evaluations were performed at 30, 45, 60, 75, and 90 days after sowing. The individual inoculation of UFSC-Pt116 isolate promoted highest height and aerial dry mass. The seedlings inoculated with the mixture UFSC-Pt116 + UFSC-Pt188 + UFSC-SA9 accumulated highest amounts of phosphorus at 90 days. The nitrogen and potassium concentrations, and root dry mass did not show significant differences among the treatments.